Cancer Genetics Risk Assessment and Counseling (PDQ®)–Health Professional Version
Executive Summary
This executive summary reviews the topics covered in this PDQ summary on cancer genetics risk assessment and genetic counseling, with hyperlinks to detailed sections below that describe the evidence on each topic.
- Identification of Individuals for Cancer Genetics Risk Assessment and CounselingIndividuals are considered to be candidates for cancer risk assessment if they have a personal and/or family history (on the maternal or paternal side) or clinical characteristics with features suggestive of hereditary cancer. These features vary by type of cancer and specific hereditary syndrome. Criteria have been published to help identify individuals who may benefit from genetic counseling. It is important that individuals who are candidates for genetic testing undergo genetic education and counseling before testing to facilitate informed decision-making and adaptation to the risk or condition. Genetic education and counseling allows individuals to consider the various medical uncertainties, diagnosis, or medical management options based on varied test results; and the risks, benefits, and limitations of genetic testing.
- Components of Cancer Genetics Risk Assessment and CounselingComprehensive cancer risk assessment and counseling is a consultative service that includes clinical assessment, genetic testing when appropriate, and risk management recommendations delivered in the context of one or more genetic counseling sessions. Pretest genetic counseling is an important part of the risk assessment process and helps patients understand their genetic testing options and potential outcomes. Posttest genetic counseling helps patients understand their test results, including the medical implications for themselves and their relatives.The recommended provision of cancer risk assessment services optimally involves care providers from multiple disciplines, including a genetic counselor; a genetics advanced practice nurse; a medical geneticist or a physician, such as an oncologist, surgeon, or internist; and potential referrals to other specialists, such as mental health professionals, endocrinologists, and reproductive specialists.Traditionally, genetic counseling services have been delivered using individualized, in-person appointments. However, other methodologies are being explored, including group sessions, telephone counseling, and telemedicine by videoconferencing.
- Genetic Testing ConsiderationsThere are many factors that can influence an individual’s decision to undergo genetic testing and which type of test to use, including the presence of a known pathogenic variant in the family, patterns of cancer in the family, insurance coverage, family planning considerations, and the psychological impact of a test result. Previously, most germline genetic testing was offered for a single gene at a time; however, recent technological advances have resulted in the widespread availability of multigene (panel) testing, which can simultaneously test for pathogenic variants in many genes at once, often at costs comparable to single-gene testing. Research examining the use of multigene testing is under way. Some genetic tests are also offered directly to the consumer (DTC). While these tests may promote patient autonomy and increased awareness of the importance of family history, DTC genetic testing may not include genetic counseling or interpretation of the results by a genetics professional.
- Ethical, Legal, and Social ImplicationsHaving an understanding of the ethical, legal, and social implications regarding cancer genetic testing may influence the clinician’s response to the complex questions and issues that may arise during the process of risk assessment and counseling. The tenets of beneficence, nonmaleficence, autonomy, and justice are part of a framework needed to balance the complex and potentially conflicting factors surrounding a clinician’s role in respecting privacy, confidentiality, and fair use of genetic information obtained from cancer genetic testing.Employment and insurance discrimination are common concerns for individuals considering genetic testing. The Genetic Information Nondiscrimination Act, a Federal law passed in 2008, protects the provision of health insurance and employment discrimination on the basis of genetics information; however, it does not apply to members of the military or to long-term care insurance.
Introduction
[Note: Many of the medical and scientific terms used in this summary are found in the NCI Dictionary of Genetics Terms. When a linked term is clicked, the definition will appear in a separate window.]
[Note: A concerted effort is being made within the genetics community to shift terminology used to describe genetic variation. The shift is to use the term “variant” rather than the term “mutation” to describe a difference that exists between the person or group being studied and the reference sequence. Variants can then be further classified as benign (harmless), likely benign, of uncertain significance, likely pathogenic, or pathogenic (disease causing). Throughout this summary, we will use the term pathogenic variant to describe a disease-causing mutation. Refer to the Cancer Genetics Overview summary for more information about variant classification.]
This summary describes current approaches to assessing and counseling people about their chance of having an inherited susceptibility to cancer. Genetic counseling is defined by the National Society of Genetic Counselors as the process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease. Several reviews present overviews of the cancer risk assessment, counseling, and genetic testing process.[1,2]
Individuals are considered to be candidates for cancer risk assessment if they have a personal and/or family history (maternal or paternal lineage) with features suggestive of hereditary cancer.[1] These features vary by type of cancer and specific hereditary syndrome. Criteria have been published to help identify individuals who may benefit from genetic counseling.[1,3] The PDQ cancer genetics information summaries on breast, ovarian, endometrial, colorectal, prostate, kidney, and skin cancers and endocrine and neuroendocrine neoplasias describe the clinical features of hereditary syndromes associated with these conditions.
- Unusually early age of cancer onset (e.g., premenopausal breast cancer).
- Multiple primary cancers in a single individual (e.g., colorectal and endometrial cancer).
- Bilateral cancer in paired organs or multifocal disease (e.g., bilateral breast cancer or multifocal renal cancer).
- Clustering of the same type of cancer in close relatives (e.g., mother, daughter, and sisters with breast cancer).
- Cancers occurring in multiple generations of a family (i.e., autosomal dominant inheritance).
- Occurrence of rare tumors (e.g., retinoblastoma, adrenocortical carcinoma, granulosa cell tumor of the ovary, ocular melanoma, or duodenal cancer).
- Occurrence of epithelial ovarian, fallopian tube, or primary peritoneal cancer.
- Unusual presentation of cancer (e.g., male breast cancer).
- Uncommon tumor histology (e.g., medullary thyroid carcinoma).
- Rare cancers associated with birth defects (e.g., Wilms tumor and genitourinary abnormalities).
- Geographic or ethnic populations known to be at high risk of hereditary cancers. Genetic testing candidates may be identified based solely on ethnicity when a strong founder effect is present in a given population (e.g., Ashkenazi heritage and BRCA1/BRCA2 pathogenic variants).
As part of the process of genetic education and counseling, genetic testing may be considered when the following factors are present:[9-11]
- An individual's personal history (including ethnicity) and/or family history are suspicious for a genetic predisposition to cancer.
- The genetic test has sufficient sensitivity and specificity to be interpreted.
- The test will impact the individual's diagnosis, cancer management or cancer risk management, and/or help clarify risk in family members.
It is important that individuals who are candidates for genetic testing undergo genetic education and counseling before testing to facilitate informed decision making and adaptation to the risk or condition.[1,7-13] Genetic education and counseling allows individuals to consider the various medical uncertainties, diagnosis, or medical management based on varied test results, and the risks, benefits, and limitations of genetic testing.
References
- Riley BD, Culver JO, Skrzynia C, et al.: Essential elements of genetic cancer risk assessment, counseling, and testing: updated recommendations of the National Society of Genetic Counselors. J Genet Couns 21 (2): 151-61, 2012. [PUBMED Abstract]
- Weitzel JN, Blazer KR, MacDonald DJ, et al.: Genetics, genomics, and cancer risk assessment: State of the Art and Future Directions in the Era of Personalized Medicine. CA Cancer J Clin 61 (5): 327-59, 2011 Sep-Oct. [PUBMED Abstract]
- Hampel H, Bennett RL, Buchanan A, et al.: A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment. Genet Med 17 (1): 70-87, 2015. [PUBMED Abstract]
- Tobias DH, Eng C, McCurdy LD, et al.: Founder BRCA 1 and 2 mutations among a consecutive series of Ashkenazi Jewish ovarian cancer patients. Gynecol Oncol 78 (2): 148-51, 2000. [PUBMED Abstract]
- Beller U, Halle D, Catane R, et al.: High frequency of BRCA1 and BRCA2 germline mutations in Ashkenazi Jewish ovarian cancer patients, regardless of family history. Gynecol Oncol 67 (2): 123-6, 1997. [PUBMED Abstract]
- Gabai-Kapara E, Lahad A, Kaufman B, et al.: Population-based screening for breast and ovarian cancer risk due to BRCA1 and BRCA2. Proc Natl Acad Sci U S A 111 (39): 14205-10, 2014. [PUBMED Abstract]
- Randall LM, Pothuri B, Swisher EM, et al.: Multi-disciplinary summit on genetics services for women with gynecologic cancers: A Society of Gynecologic Oncology White Paper. Gynecol Oncol 146 (2): 217-224, 2017. [PUBMED Abstract]
- Committee on Practice Bulletins–Gynecology, Committee on Genetics, Society of Gynecologic Oncology: Practice Bulletin No 182: Hereditary Breast and Ovarian Cancer Syndrome. Obstet Gynecol 130 (3): e110-e126, 2017. [PUBMED Abstract]
- Robson ME, Storm CD, Weitzel J, et al.: American Society of Clinical Oncology policy statement update: genetic and genomic testing for cancer susceptibility. J Clin Oncol 28 (5): 893-901, 2010. [PUBMED Abstract]
- Lancaster JM, Powell CB, Chen LM, et al.: Society of Gynecologic Oncology statement on risk assessment for inherited gynecologic cancer predispositions. Gynecol Oncol 136 (1): 3-7, 2015. [PUBMED Abstract]
- Robson ME, Bradbury AR, Arun B, et al.: American Society of Clinical Oncology Policy Statement Update: Genetic and Genomic Testing for Cancer Susceptibility. J Clin Oncol 33 (31): 3660-7, 2015. [PUBMED Abstract]
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Breast and Ovarian. Version 3.2019. Plymouth Meeting, Pa: National Comprehensive Cancer Network, 2019. Available online with free registration. Last accessed January 29, 2019.
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Colorectal. Version 1.2018. Plymouth Meeting, PA: National Comprehensive Cancer Network, 2018. Available online with free registration. Last accessed October 22, 2018.
Identification of Candidates for Referral to Genetic Counseling
After an individual’s personal and family cancer histories have been collected, several factors could warrant referral to a genetics professional for evaluation of hereditary cancer susceptibility syndromes. The American College of Medical Genetics and Genomics and the National Society of Genetic Counselors have published a comprehensive set of personal and family history criteria to guide the identification of at-risk individuals and appropriate referral for cancer genetic risk consultation.[1] These practice guidelines take into account tumor types or other features and related criteria that would indicate a need for a genetics referral. The authors state that the guidelines are intended to maximize appropriate referral of at-risk individuals for cancer genetic consultation but are not meant to provide genetic testing or treatment recommendations.
Tools to Identify Candidates for Genetic Counseling and Genetic Testing
Identification of patients at moderate to high risk of hereditary cancer for genetic services is recommended by all major societies. Primary care physicians have a number of tools available to triage patients. In addition to the published categorical guidelines available through professional organizations,[1-4] there are also red flag cards, paper-based checklists, and patient-directed online referral tools. Table 1 provides a list of several publically available resources that can be used to identify patients for referral to genetic services. Although most tools are brief and simple enough for patients to complete on their own, either previsit, online, or in the waiting room, clinical review is warranted. Many include the commonly known features suggestive of hereditary cancers, but exclusions are noted in the table below.
There are also more extensive statistical risk assessment models designed for both highly motivated patients [17,18] and genetic specialists (e.g., CancerGene, IBIS).
References
- Hampel H, Bennett RL, Buchanan A, et al.: A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment. Genet Med 17 (1): 70-87, 2015. [PUBMED Abstract]
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Breast and Ovarian. Version 3.2019. Plymouth Meeting, Pa: National Comprehensive Cancer Network, 2019. Available online with free registration. Last accessed January 29, 2019.
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Colorectal. Version 1.2018. Plymouth Meeting, PA: National Comprehensive Cancer Network, 2018. Available online with free registration. Last accessed October 22, 2018.
- Lancaster JM, Powell CB, Chen LM, et al.: Society of Gynecologic Oncology statement on risk assessment for inherited gynecologic cancer predispositions. Gynecol Oncol 136 (1): 3-7, 2015. [PUBMED Abstract]
- Bellcross CA, Lemke AA, Pape LS, et al.: Evaluation of a breast/ovarian cancer genetics referral screening tool in a mammography population. Genet Med 11 (11): 783-9, 2009. [PUBMED Abstract]
- Bellcross C: Further development and evaluation of a breast/ovarian cancer genetics referral screening tool. Genet Med 12 (4): 240, 2010. [PUBMED Abstract]
- Brannon Traxler L, Martin ML, Kerber AS, et al.: Implementing a screening tool for identifying patients at risk for hereditary breast and ovarian cancer: a statewide initiative. Ann Surg Oncol 21 (10): 3342-7, 2014. [PUBMED Abstract]
- Emery JD, Reid G, Prevost AT, et al.: Development and validation of a family history screening questionnaire in Australian primary care. Ann Fam Med 12 (3): 241-9, 2014 May-Jun. [PUBMED Abstract]
- Gilpin CA, Carson N, Hunter AG: A preliminary validation of a family history assessment form to select women at risk for breast or ovarian cancer for referral to a genetics center. Clin Genet 58 (4): 299-308, 2000. [PUBMED Abstract]
- Ashton-Prolla P, Giacomazzi J, Schmidt AV, et al.: Development and validation of a simple questionnaire for the identification of hereditary breast cancer in primary care. BMC Cancer 9: 283, 2009. [PUBMED Abstract]
- Hoskins KF, Zwaagstra A, Ranz M: Validation of a tool for identifying women at high risk for hereditary breast cancer in population-based screening. Cancer 107 (8): 1769-76, 2006. [PUBMED Abstract]
- Teller P, Hoskins KF, Zwaagstra A, et al.: Validation of the pedigree assessment tool (PAT) in families with BRCA1 and BRCA2 mutations. Ann Surg Oncol 17 (1): 240-6, 2010. [PUBMED Abstract]
- Cohn WF, Jones SM, Miesfeldt S: "Are you at risk for hereditary breast cancer?": development of a personal risk assessment tool for hereditary breast and ovarian cancer. J Genet Couns 17 (1): 64-78, 2008. [PUBMED Abstract]
- Fisher TJ, Kirk J, Hopper JL, et al.: A simple tool for identifying unaffected women at a moderately increased or potentially high risk of breast cancer based on their family history. Breast 12 (2): 120-7, 2003. [PUBMED Abstract]
- Stewart SL, Kaplan CP, Lee R, et al.: Validation of an Efficient Screening Tool to Identify Low-Income Women at High Risk for Hereditary Breast Cancer. Public Health Genomics 19 (6): 342-351, 2016. [PUBMED Abstract]
- Rabinowitz-Abrams D, Morgan D, Morse J, et al.: Building a tool to identify risk for Lynch syndrome among individuals presenting for screening colonoscopy. J Genet Couns 19 (4): 353-9, 2010. [PUBMED Abstract]
- Sweet K, Sturm AC, Rettig A, et al.: Clinically relevant lessons from Family HealthLink: a cancer and coronary heart disease familial risk assessment tool. Genet Med 17 (6): 493-500, 2015. [PUBMED Abstract]
- Baumgart LA, Postula KJ, Knaus WA: Initial clinical validation of Health Heritage, a patient-facing tool for personal and family history collection and cancer risk assessment. Fam Cancer 15 (2): 331-9, 2016. [PUBMED Abstract]
Cancer Risk Assessment and Counseling
Comprehensive cancer risk assessment is a consultative service that includes clinical assessment, genetic testing when appropriate, and risk management recommendations delivered in the context of one or more genetic counseling sessions. Pretest genetic counseling is an important part of the risk assessment process and helps patients understand their genetic testing options and potential outcomes. Posttest genetic counseling helps patients understand their test results, including the medical implications for themselves and their relatives.
The following professional organizations emphasize the importance of genetic counseling in the cancer risk assessment and genetic testing process:
- American College of Medical Genetics and Genomics.[1]
- American College of Obstetrics and Gynecology.[2]
- American Society of Clinical Oncology.[3,4]
- American Society of Human Genetics.[5,6]
- International Society of Nurses in Genetics.[7,8]
- National Society of Genetic Counselors.[9-11]
- National Comprehensive Cancer Network.[12,13]
- Oncology Nursing Society.[14]
- Society of Gynecologic Oncologists.[15,16]
- U.S. Preventive Services Task Force.[17]
A list of organizations that have published clinical practices guidelines related to genetic counseling, risk assessment, genetic testing, and/or management for hereditary breast and ovarian cancers is available in the PDQ summary on Genetics of Breast and Gynecologic Cancers.
Genetic counseling informs the consultand about potential cancer risks and the benefits and limitations of genetic testing and offers an opportunity to consider the potential medical, psychological, familial, and social implications of genetic information.[9,18] Descriptions of genetic counseling and the specialized practice of cancer risk assessment counseling are detailed below.
Genetic Counseling
Genetic counseling has been defined by the National Society of Genetic Counselors as the process of helping people understand and adapt to the medical, psychological, and familialimplications of genetic contributions to disease, including the following:[9]
- How inherited diseases and conditions might affect them or their families.
- How family and medical histories may impact the chance of disease occurrence or recurrence.
- Which genetic tests may or may not be right for them, and what those tests may or may not tell.
- How to make the most informed choices about health care conditions.
Traditionally, genetic counseling services have been delivered using individualized in-person appointments. However, other methodologies have been implemented, including group sessions, telephone counseling, and online genetic counseling using remote videoconferencing, which is often referred to as telegenetics. (Refer to the Modalities of genetic counseling section of this summary for more information.)
Central to the philosophy and practice of genetic counseling are the principles of voluntary utilization of services, informed decision making, attention to psychosocial and affective dimensions of coping with genetic risk, and protection of patient confidentiality and privacy. This is facilitated through a combination of rapport building and information gathering; establishing or verifying diagnoses; risk assessment and calculation of quantitative occurrence/recurrence risks; education and informed consent processes; psychosocial assessment, support, and counseling appropriate to a family’s culture and ethnicity; and other relevant background characteristics.[19,20] The psychosocial assessment is especially important in the genetic counseling process because individuals most vulnerable to adverse effects of genetic information may include those who have had difficulty dealing with stressful life events in the past.[21] Variables that may influence psychosocial adjustment to genetic information include individual and familial factors; cultural factors; and health system factors such as the type of test, disease status, and risk information.[21] Findings from a psychosocial assessment can be used to help guide the direction of the counseling session.[10] An important objective of genetic counseling is to provide an opportunity for shared decision making when the medical benefits of one course of action are not demonstrated to be superior to another. The relationship between the availability of effective medical treatment for carriers of pathogenic variants and the clinical validity of a given test affects the degree to which personal choice or physician recommendation is supported in counseling at-risk individuals.[22] Uptake of genetic counseling services among those referred varies based on the cancer syndrome and the clinical setting. Efforts to decrease barriers to service utilization are ongoing (e.g., the use of a patient navigator or an oncology clinic–based genetic counselor may increase utilization of these services).[23-25] Readers interested in the nature and history of genetic counseling are referred to a number of comprehensive reviews.[26-31]
Pretest Genetic Education and Counseling Outcomes
Cancer risk assessment counseling has emerged as a specialized practice that requires knowledge of genetics, oncology, and individual and family counseling skills that may be provided by health care providers with this interdisciplinary training.[32] Some centers providing cancer risk assessment services involve a multidisciplinary team, which may include a genetic counselor; a genetics advanced practice nurse; a medical geneticist or a physician, such as an oncologist, surgeon, or internist; and a mental health professional. The Cancer Genetics Services Directory provides a partial list of individuals involved in cancer risk assessment, genetic counseling, testing, and other related services and is available on the National Cancer Institute's website.
Modalities of genetic counseling
Traditionally, genetic counseling services have been delivered using individualized in-person appointments. However, other methodologies have been implemented, including group sessions, telephone counseling, and online genetic counseling using remote videoconferencing, which is often referred to as telegenetics.[33-41] Of these alternative approaches, only telephone counseling has been examined for noninferiority against in-person genetic counseling in a randomized controlled trial.[42-45]
Telephone genetic counseling
A systematic review identified 13 published studies that used a randomized controlled trial design to compare pretest and posttest outcomes for in-person genetic counseling with telephone counseling. Knowledge and psychosocial outcomes (e.g., distress) were found to be noninferior, equivalent, or not statistically significant between telephone counseling and in-person counseling. Two studies demonstrated lower testing intention or uptake among participants receiving telephone counseling. The majority of studies also found no difference in satisfaction; however, two studies demonstrated higher satisfaction among individuals who received telephone versus in-person genetic counseling.[45] (The studies were conducted prior to the adoption of multigene panel testing.)
Another group reported results of a study where all participants (N = 1,178) received in-person pretest counseling at one of five participating sites. Those participants willing to be randomized had their results disclosed by telephone (n = 401) or in person (n = 418). Notably, 30% of participants in this study had multigene panel testing. In this trial, telephone disclosure was noninferior to in-person results disclosure when comparing primary psychosocial outcomes (e.g., general and state anxiety). In primary analysis, knowledge did not meet the threshold of noninferiority without imputing missing data. Secondary outcomes related to cancer distress, depression, uncertainty, satisfaction with genetic testing, and behavioral intentions for risk management strategies were not statistically significant between groups.[46]
Video-assisted genetic counseling
References
- Hampel H, Bennett RL, Buchanan A, et al.: A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment. Genet Med 17 (1): 70-87, 2015. [PUBMED Abstract]
- Committee on Practice Bulletins–Gynecology, Committee on Genetics, Society of Gynecologic Oncology: Practice Bulletin No 182: Hereditary Breast and Ovarian Cancer Syndrome. Obstet Gynecol 130 (3): e110-e126, 2017. [PUBMED Abstract]
- Robson ME, Storm CD, Weitzel J, et al.: American Society of Clinical Oncology policy statement update: genetic and genomic testing for cancer susceptibility. J Clin Oncol 28 (5): 893-901, 2010. [PUBMED Abstract]
- Robson ME, Bradbury AR, Arun B, et al.: American Society of Clinical Oncology Policy Statement Update: Genetic and Genomic Testing for Cancer Susceptibility. J Clin Oncol 33 (31): 3660-7, 2015. [PUBMED Abstract]
- Botkin JR, Belmont JW, Berg JS, et al.: Points to Consider: Ethical, Legal, and Psychosocial Implications of Genetic Testing in Children and Adolescents. Am J Hum Genet 97 (1): 6-21, 2015. [PUBMED Abstract]
- Statement of the American Society of Human Genetics on genetic testing for breast and ovarian cancer predisposition. Am J Hum Genet 55 (5): i-iv, 1994. [PUBMED Abstract]
- International Society of Nurses in Genetics: Provision of Quality Genetic Services and Care: Building a Multidisciplinary, Collaborative Approach among Genetic Nurses and Genetic Counselors. Pittsburgh, Pa: International Society of Nurses in Genetics, 2006. Available online. Last accessed December 07, 2018.
- International Society of Nurses in Genetics: Genetic Counseling for Vulnerable Populations: The Role of Nursing. Pittsburgh, Pa: International Society of Nurses in Genetics, 2010. Available online. Last accessed December 07, 2018.
- Resta R, Biesecker BB, Bennett RL, et al.: A new definition of Genetic Counseling: National Society of Genetic Counselors' Task Force report. J Genet Couns 15 (2): 77-83, 2006. [PUBMED Abstract]
- Riley BD, Culver JO, Skrzynia C, et al.: Essential elements of genetic cancer risk assessment, counseling, and testing: updated recommendations of the National Society of Genetic Counselors. J Genet Couns 21 (2): 151-61, 2012. [PUBMED Abstract]
- Berliner JL, Fay AM, Cummings SA, et al.: NSGC practice guideline: risk assessment and genetic counseling for hereditary breast and ovarian cancer. J Genet Couns 22 (2): 155-63, 2013. [PUBMED Abstract]
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Breast and Ovarian. Version 3.2019. Plymouth Meeting, Pa: National Comprehensive Cancer Network, 2019. Available online with free registration. Last accessed January 29, 2019.
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Colorectal. Version 1.2018. Plymouth Meeting, PA: National Comprehensive Cancer Network, 2018. Available online with free registration. Last accessed October 22, 2018.
- Oncology nursing: the application of cancer genetics and genomics throughout the oncology care continuum. Oncol Nurs Forum 40 (1): 10-1, 2013. [PUBMED Abstract]
- Lancaster JM, Powell CB, Chen LM, et al.: Society of Gynecologic Oncology statement on risk assessment for inherited gynecologic cancer predispositions. Gynecol Oncol 136 (1): 3-7, 2015. [PUBMED Abstract]
- Randall LM, Pothuri B, Swisher EM, et al.: Multi-disciplinary summit on genetics services for women with gynecologic cancers: A Society of Gynecologic Oncology White Paper. Gynecol Oncol 146 (2): 217-224, 2017. [PUBMED Abstract]
- Moyer VA; U.S. Preventive Services Task Force: Risk assessment, genetic counseling, and genetic testing for BRCA-related cancer in women: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 160 (4): 271-81, 2014. [PUBMED Abstract]
- Resta RG: Defining and redefining the scope and goals of genetic counseling. Am J Med Genet C Semin Med Genet 142C (4): 269-75, 2006. [PUBMED Abstract]
- Baty BJ, Kinney AY, Ellis SM: Developing culturally sensitive cancer genetics communication aids for African Americans. Am J Med Genet 118A (2): 146-55, 2003. [PUBMED Abstract]
- Jenkins JF, Lea DH: Nursing Care in the Genomic Era: A Case-Based Approach. Sudbury, Mass: Jones and Bartlett Publishers, 2005.
- Meiser B, Gaff C, Julian-Reynier C, et al.: International perspectives on genetic counseling and testing for breast cancer risk. Breast Dis 27: 109-25, 2006-2007. [PUBMED Abstract]
- Burke W, Pinsky LE, Press NA: Categorizing genetic tests to identify their ethical, legal, and social implications. Am J Med Genet 106 (3): 233-40, 2001 Fall. [PUBMED Abstract]
- Rahm AK, Sukhanova A, Ellis J, et al.: Increasing utilization of cancer genetic counseling services using a patient navigator model. J Genet Couns 16 (2): 171-7, 2007. [PUBMED Abstract]
- Kentwell M, Dow E, Antill Y, et al.: Mainstreaming cancer genetics: A model integrating germline BRCA testing into routine ovarian cancer clinics. Gynecol Oncol 145 (1): 130-136, 2017. [PUBMED Abstract]
- Kishan AU, Gomez CL, Dawson NA, et al.: Increasing Appropriate BRCA1/2 Mutation Testing: The Role of Family History Documentation and Genetic Counseling in a Multidisciplinary Clinic. Ann Surg Oncol 23 (Suppl 5): 634-641, 2016. [PUBMED Abstract]
- Walker AP: The practice of genetic counseling. In: Baker DL, Schuette JL, Uhlmann WR, eds.: A Guide to Genetic Counseling. New York, NY: Wiley-Liss, 1998, pp 1-26.
- Bartels DM, LeRoy BS, Caplan AL, eds.: Prescribing Our Future: Ethical Challenges in Genetic Counseling. New York, NY: Aldine De Gruyter, 1993.
- Kenen RH: Genetic counseling: the development of a new interdisciplinary occupational field. Soc Sci Med 18 (7): 541-9, 1984. [PUBMED Abstract]
- Kenen RH, Smith AC: Genetic counseling for the next 25 years: models for the future. J Genet Couns 4 (2): 115-24, 1995.
- Biesecker BB: Goals of genetic counseling. Clin Genet 60 (5): 323-30, 2001. [PUBMED Abstract]
- Weil Jon: Psychosocial Genetic Counseling. New York, NY: Oxford University Press, 2000.
- Freedman AN, Wideroff L, Olson L, et al.: US physicians' attitudes toward genetic testing for cancer susceptibility. Am J Med Genet A 120A (1): 63-71, 2003. [PUBMED Abstract]
- Ormond K: Recommendations for telephone counseling. J Genet Couns 9 (1): 63-71, 2000.
- Sangha K: Assessment of the effectiveness of genetic counseling by telephone compared to a clinic visit. J Genet Couns 12 (2): 171-84, 2003.
- Calzone KA, Prindiville SA, Jourkiv O, et al.: Randomized comparison of group versus individual genetic education and counseling for familial breast and/or ovarian cancer. J Clin Oncol 23 (15): 3455-64, 2005. [PUBMED Abstract]
- Jenkins J, Calzone KA, Dimond E, et al.: Randomized comparison of phone versus in-person BRCA1/2 predisposition genetic test result disclosure counseling. Genet Med 9 (8): 487-95, 2007. [PUBMED Abstract]
- Peshkin BN, Demarco TA, Graves KD, et al.: Telephone genetic counseling for high-risk women undergoing BRCA1 and BRCA2 testing: rationale and development of a randomized controlled trial. Genet Test 12 (1): 37-52, 2008. [PUBMED Abstract]
- Zilliacus EM, Meiser B, Lobb EA, et al.: Women's experience of telehealth cancer genetic counseling. J Genet Couns 19 (5): 463-72, 2010. [PUBMED Abstract]
- Rothwell E, Kohlmann W, Jasperson K, et al.: Patient outcomes associated with group and individual genetic counseling formats. Fam Cancer 11 (1): 97-106, 2012. [PUBMED Abstract]
- Platten U, Rantala J, Lindblom A, et al.: The use of telephone in genetic counseling versus in-person counseling: a randomized study on counselees' outcome. Fam Cancer 11 (3): 371-9, 2012. [PUBMED Abstract]
- Benusiglio PR, Di Maria M, Dorling L, et al.: Hereditary breast and ovarian cancer: successful systematic implementation of a group approach to genetic counselling. Fam Cancer 16 (1): 51-56, 2017. [PUBMED Abstract]
- Schwartz MD, Valdimarsdottir HB, Peshkin BN, et al.: Randomized noninferiority trial of telephone versus in-person genetic counseling for hereditary breast and ovarian cancer. J Clin Oncol 32 (7): 618-26, 2014. [PUBMED Abstract]
- Kinney AY, Steffen LE, Brumbach BH, et al.: Randomized Noninferiority Trial of Telephone Delivery of BRCA1/2 Genetic Counseling Compared With In-Person Counseling: 1-Year Follow-Up. J Clin Oncol 34 (24): 2914-24, 2016. [PUBMED Abstract]
- Kinney AY, Butler KM, Schwartz MD, et al.: Expanding access to BRCA1/2 genetic counseling with telephone delivery: a cluster randomized trial. J Natl Cancer Inst 106 (12): , 2014. [PUBMED Abstract]
- Athens BA, Caldwell SL, Umstead KL, et al.: A Systematic Review of Randomized Controlled Trials to Assess Outcomes of Genetic Counseling. J Genet Couns 26 (5): 902-933, 2017. [PUBMED Abstract]
- Bradbury AR, Patrick-Miller LJ, Egleston BL, et al.: Randomized Noninferiority Trial of Telephone vs In-Person Disclosure of Germline Cancer Genetic Test Results. J Natl Cancer Inst : , 2018. [PUBMED Abstract]
- Otten E, Birnie E, Ranchor AV, et al.: Telegenetics use in presymptomatic genetic counselling: patient evaluations on satisfaction and quality of care. Eur J Hum Genet 24 (4): 513-20, 2016. [PUBMED Abstract]
- Buchanan AH, Datta SK, Skinner CS, et al.: Randomized Trial of Telegenetics vs. In-Person Cancer Genetic Counseling: Cost, Patient Satisfaction and Attendance. J Genet Couns 24 (6): 961-70, 2015. [PUBMED Abstract]
- Bradbury A, Patrick-Miller L, Harris D, et al.: Utilizing Remote Real-Time Videoconferencing to Expand Access to Cancer Genetic Services in Community Practices: A Multicenter Feasibility Study. J Med Internet Res 18 (2): e23, 2016. [PUBMED Abstract]
Components of the Risk Assessment Process
This section provides an overview of critical elements in the cancer risk assessmentprocess.
A number of professional guidelines on the elements of cancer genetics risk assessment and counseling are available.[1-5] Except where noted, the discussion below is based on these guidelines.
The cancer risk assessment and genetic counseling process consists of one or more consultative sessions and generally includes the following:
- A detailed, multifaceted assessment including medical, psychosocial, and family history.
- A determination of the risk of cancer and/or indication for genetic testing based on evidence of an inherited cancer syndrome.
- Education and counseling about familial /hereditary cancer risks.
- If appropriate, review of genetic testing options as well as potential limitations, risks, and benefits of testing.
- Establishment of a cancer risk management plan.
- Discussion of follow-up plans, provision of referrals, educational materials, etc.
Assessment
At the outset of the initial counseling session, eliciting and addressing the consultand'sperceptions and concerns about cancer and his or her expectations of the risk assessment process helps to engage the consultand in the session. This also helps inform the provider about practical or psychosocial issues and guides the focus of counseling and strategies for risk assessment.
Psychosocial assessment
The counseling process that takes place as part of a cancer risk assessment can identify factors that contribute to the consultand's perception of cancer risk and motivations to seek cancer risk assessment and genetic testing. It can also identify potential psychological issues that may need to be addressed during or after the session, particularly after genetic testing. Information collected before and/or during the session may include the following:
- Motivations for seeking cancer risk assessment.
- Beliefs about the causes of cancer.
- Experiences with cancer and feelings, perceptions, concerns, or fears related to those experiences.
- The influence of cancer experiences and perceptions on health behaviors and cancer screening practices.
- Cultural, religious, and socioeconomic background.
- General psychological history, such as depression or anxiety, and medication use.
- Coping mechanisms.
- Support systems.
Either alone or in consultation with a mental health provider, health care providers offering cancer risk counseling attempt to assess whether there are factors suggesting risk of adverse psychological outcomes after disclosure of risk and/or genetic status.
Risk perception
Clinical Evaluation
Personal health history
Consideration of the consultand's personal health history is essential in cancer risk assessment, regardless of whether the individual has a personal history of cancer. Important information to obtain about the consultand's health history includes the following:[1,3]
- Current age.
- Race, ancestry, and ethnicity.
- History of benign or precancerous tumors or polyps, surgeries, biopsies, major illnesses, medications, and reproductive history (for women, this includes age at menarche, parity, age at first live birth, age at menopause, and history of exogenous hormone use).
- Screening practices and date of last screening exams, including imaging and/or physical examinations.
- Environmental exposures.
- Past and current alcohol intake and tobacco use.
- Diet, exercise, and complementary and alternative medicine practices may also be assessed.
For consultands with a history of cancer, additional information collected includes the following:
- Site/type of primary malignancy and any metastasis or recurrence.
- Age at diagnosis.
- Pathology findings/staging.
- Prior germline genetic testing results.
- Prior tumor testing results (including genomic profiling). (Refer to the Clinical Sequencing section in the Cancer Genetics Overview PDQ summary for more information about the implications of tumor testing.)
- Treatment (e.g., surgery, chemotherapy, radiation therapy, targeted therapy), including whether genetic risk assessment may affect treatment.
- Bilaterality of disease, if applicable.
- Current surveillance plan.
- Carcinogenic exposures (e.g., alcohol and tobacco use, sun exposure, radiation exposure, asbestos exposure) or other known cancer site-specific risk factors.
- How the cancer was detected (e.g., self-exam, screening test, presenting symptoms) may also be assessed.
Physical examination
In some cases, a physical exam is conducted by a qualified medical professional to determine whether the individual has physical findings suggestive of a hereditary cancer predisposition syndrome or to rule out evidence of an existing malignancy. For example, a medical professional may look for the sebaceous adenomas seen in Muir-Torre syndrome, measure the head circumference or perform a skin exam to rule out benign cutaneous features associated with Cowden syndrome, or perform a clinical breast and axillary lymph node exam on a woman undergoing a breast cancer risk assessment.
Family history
Documenting the family history
The family history is an essential tool for cancer risk assessment. The family history can be obtained via interview or written self-report; both were found to result in equivalent information.[10] Studies suggest that paper-based family history questionnaires completed before the appointment provide accurate family history information [11] and that the use of these questionnaires is an acceptable and understandable family history collection method.[12] Both multimedia-based (e.g., Internet) and print-based (e.g., family history questionnaires) tools are currently available to gather information about family history. However, on average, print-based tools have been found to be written at lower reading grade levels than multimedia-based tools.[13] It has been reported that questionnaire-based assessments may lead to some underreporting of family history; therefore, a follow-up interview to confirm the reported information and to capture all relevant family history information may be required.[14] Collecting family history from multiple relatives in a single family has been shown to increase the number of family members reported to have cancer, compared with family history information provided by a single family member.[15]
Details of the family health history are best summarized in the form of a family tree, or pedigree. The pedigree, a standardized graphic representation of family relationships, facilitates identification of patterns of disease transmission, recognition of the clinical characteristics associated with specific hereditary cancer syndromes, and determination of the best strategies and tools for risk assessment.[16,17]
Standards of pedigree nomenclature have been established.[16,17] Refer to Figure 1 for common pedigree symbols.
Refer to the paragraph below for descriptions of factors suggesting inherited cancer risk.
Documentation of a comprehensive family cancer history typically includes the following:
- A three-generation pedigree consisting of a minimum of first- and second-degree relatives on both the maternal and paternal sides of the family. Information on multiple generations helps to demonstrate inheritance patterns. Hereditary cancer can be inherited from either the maternal or paternal side of the family and is often an adult-onset disease.[18]
- Race, ancestry, and ethnicity of all grandparents. This may influence decisions about genetic testing because specific pathogenic variants in some genes are known to occur with increased frequency in some populations (founder effect).[18]
- Information about seemingly unrelated conditions, such as birth defects, atypical skin bumps, or other nonmalignant conditions of children and adults that may aid in the diagnosis of a cancer susceptibility syndrome.
- Notation of adoption, nonpaternity (the biologic father should be included in the pedigree), consanguinity, and use of assisted reproductive technology (e.g., donor egg or sperm).
A three-generation family history includes the following:
- First-degree relatives (e.g., children, brothers and sisters, and parents).
- Second-degree relatives (e.g., grandparents, aunts and uncles, nieces and nephews, grandchildren, and half-siblings).
- Third-degree relatives (e.g., first cousins, great aunts, and great uncles).
- Additional distant relatives are included if information is available, especially when there are known cancer histories among them.
For any relative with cancer, collect the following information:[19]
- Primary site of each cancer. Obtaining medical documentation of key cancers (e.g., pathology reports, clinical documents, and death certificates) is especially relevant to risk assessment and/or management recommendations. (Refer to the Accuracy of the family history section of this summary for more information.)
- Age at diagnosis for each primary cancer.
- Where the relative was diagnosed and/or treated.
- History of surgery or treatments that may have reduced the risk of cancer. For example, bilateral salpingo-oophorectomy in a premenopausal woman significantly reduces the risk of ovarian and breast cancers. This may mask underlying hereditary predisposition to these cancers.
- Current age (if living).
- Age at death and cause of death (if deceased).
- Carcinogenic exposures (e.g., alcohol and tobacco use, sun exposure, radiation exposure, asbestos exposure) or other known cancer site-specific risk factors.
- Prior germline genetic testing results.
- Prior tumor testing results (including genomic profiling).
- Other significant health problems.
For relatives not affected with cancer, collect the following information:
- Current age or age at death.
- Cause of death (if deceased).
- History of any surgeries or treatments that may have reduced the risk of cancer.
- Cancer screening practices.
- Any nonmalignant features associated with the syndrome in question.
- Carcinogenic exposures (e.g., alcohol and tobacco use, sun exposure, radiation exposure, asbestos exposure) or other known cancer site-specific risk factors.
- Prior germline genetic testing results.
- Prior tumor testing results (including genomic profiling).
- Other significant health problems.
Accuracy of the family history
The accuracy of the family history has a direct bearing on determining the differential diagnoses, selecting appropriate testing, interpreting results of the genetic tests, refining individual cancer risk estimates, and outlining screening and risk reduction recommendations. In a telephone survey of 1,019 individuals, only 6% did not know whether a first-degree relative had cancer; this increased to 8.5% for second-degree relatives.[20] However, people often have incomplete or inaccurate information about the cancer history in their family.[17,19,21-27] Patient education has been shown to improve the completeness of family history collection and may lead to more-accurate risk stratification, referrals for genetic counseling, and changes to management recommendations.[28] Confirming the primary site of cancers in the family that will affect the calculation of hereditary predisposition probabilities and/or estimation of empiric cancer risks may be important, especially if decisions about treatments such as risk-reducing surgery will be based on this family history.[23,29]
Accuracy varies by cancer site and degree of relatedness.[25,30,31] Reporting of cancer family histories may be most accurate for breast cancer [25,31] and less accurate for gynecologic malignancies [25,31] and colon cancer.[25] Self-reported family histories may contain errors and, in rare instances, could be fictitious.[23,29,31] The most reliable documentation of cancer histology is the pathology report. Verification of cancers can also be made through other medical records, tumor registries, or death certificates.
Determining Cancer Risk
Analysis of the family history
Because a family history of cancer is one of the important predictors of cancer risk, analysis of the pedigree constitutes an important aspect of risk assessment. This analysis might be thought of as a series of the following questions:
- What is the evidence that a cancer susceptibility syndrome is present in this family?
- If a syndrome is suspected, what are the differential diagnoses?
- What could make the family history difficult to interpret?
- What is the most likely mode of inheritance, regardless of whether a syndrome diagnosis can be established?
- What is the chance of a member of this family developing cancer, if an inherited susceptibility exists?
- If no recognizable syndrome is present, is there a risk of cancer based on other epidemiological risk factors?
- What is the evidence that a cancer susceptibility syndrome is present in this family?The clues to a hereditary syndrome are based on pedigree analysis and physical findings. The index of suspicion is raised by the following:[18]
- Multiple cancers in close relatives, particularly in multiple generations.
- Early age of cancer onset (younger than age 40 to 50 y for adult-onset cancers).
- Multiple primary cancers in a single individual.
- Bilateral cancers.
- Recognition of the known association between etiologically related cancers in the family (e.g., breast and ovarian cancers; colon and endometrial cancers).
- Presence of congenital anomalies or precursor lesions that are known to be associated with increased cancer risk (e.g., presence of atypical nevi and risk of malignant melanoma).
- Recognizable mendelian inheritance pattern.
- Specific tumor types or pathologies associated with germline pathogenic variants in cancer susceptibility genes, regardless of family history (e.g., ovarian cancer, medullary thyroid cancer, triple-negative breast cancer, sex cord tumors in ovarian cancer). (Refer to the PDQ summaries on Genetics of Breast and Gynecologic Cancers and Genetics of Endocrine and Neuroendocrine Neoplasias for more information about these tumor types and the associated genes.)
- Abnormal results from colon or endometrial tumor testing with microsatellite instability or immunohistochemistry, suggestive of Lynch syndrome. (Refer to the Genetics of Lynch syndrome section in the PDQ summary on Genetics of Colorectal Cancer for more information.)
- Somatic variants identified from tumor genomic profiling that may be present in the germline.
Clinical characteristics associated with different cancer genetic syndromes are summarized in the following comprehensive set of personal and family history criteria published by the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors.[32] These practice guidelines take into account tumor types or other features and related criteria that would indicate a need for a genetics referral. The authors state that the guidelines are intended to maximize appropriate referral of at-risk individuals for cancer genetic consultation but are not meant to provide genetic testing or treatment recommendations. - If a syndrome is suspected, what are the differential diagnoses?The most commonly encountered indications for genetic counseling/testing are for suspected hereditary breast cancer or hereditary colon cancer syndromes.For hereditary breast cancer, genetic counseling and testing criteria are broad.[32,33] Multigene panel testing has revealed that pathogenic variants in several other high- and moderate-penetrance genes other than BRCA1 and BRCA2 contribute to this phenotype, such as PALB2, CHEK2, and ATM.For hereditary colon cancer syndromes, differential diagnoses are based on several factors, including the number and type of colorectal polyps and histopathology of gastrointestinal and other malignancies.[34,35] However, in the absence of polyposis and rare pathologies, Lynch syndrome is frequently in the differential. Furthermore, Lynch syndrome may be in the differential diagnoses list even when there are cases of breast and/or ovarian cancer in the family that are not consistent with hereditary breast and ovarian cancer.[36,37] (Refer to the Lynch syndrome section in the PDQ summary on Genetics of Colorectal Cancer for more information.)Diagnostic and testing criteria exist for several rare syndromes such as Li-Fraumeni,[38] Cowden,[39,40] multiple endocrine neoplasias,[41] and familial adenomatous polyposis.[34] In some cases, pathognomonic features are also an indicator for a likely diagnosis.[39,40]Based on these considerations, genetic testing options may consist of limited targeted testing for pathogenic variants in one or a small number of genes, or may consist of larger gene panels.
- What could make the family history difficult to interpret?Other factors may complicate recognition of basic inheritance patterns or represent different types of disease etiology.[42-44]Common examples of complicating factors related to family history structure include the following:
- Small family size.
- Incomplete information due to lack of knowledge of family history (e.g., due to adoption or lack of information about cancers in relatives).
- Gender imbalance (e.g., few women in a family suspected of hereditary breast cancer).
- Deaths at particularly early ages.
- Removal of the at-risk organ, either for risk reduction or as a result of a medical condition (e.g., hysterectomy due to history of uterine fibroids or endometriosis may hamper the identification of Lynch syndrome).
- Misattributed parentage.
- Consanguinity.
Genetic factors that may affect family history interpretation include:- Late or variable onset of disease.
- Nonpenetrance.
- Variable expression.
- Genetic heterogeneity.
- De novo pathogenic variant.
- Mosaicism (somatic or germline).
- What is the most likely mode of inheritance, regardless of whether a syndrome diagnosis can be established?The mode of inheritance refers to the way that genetic traits are transmitted in the family.Most commonly, inheritance patterns are established by a combination of clinical diagnosis with a compatible, but not necessarily in itself conclusive, pedigree pattern.[45] Most recognized hereditary cancer syndromes are autosomal dominant or autosomal recessive. Clues to recognizing these patterns within a pedigree are described below. (Refer to question 3, What could make the family history difficult to interpret?, for a list of situations that may complicate pedigree interpretation.)Autosomal dominant
- Autosomal dominant inheritance refers to disorders that are expressed in the heterozygote (i.e., the affected person has one copy of a variant allele and one allele that is functioning normally). All the major hereditary breast/ovarian cancer syndromes including BRCA1/BRCA2, Li-Fraumeni, and Cowden, as well as the major hereditary colon cancer syndrome, Lynch syndrome, are inherited in this fashion. Autosomal dominant inheritance is characterized by the following:
- Vertical occurrence (i.e., seen in successive generations).
- Usually seen only on one side of the family (i.e., unipaternal or unimaternal).
- Males and females may inherit and transmit the disorder to offspring.
- Male-to-male transmission may be seen.
- Offspring have a 50% chance of inheriting a pathogenic variant and a 50% chance of inheriting the normal allele.
- The condition may appear to skip a generation due to incomplete penetrance, early death due to other causes, delayed age of onset, or paucity of males or females when the at-risk organ is gender-specific (e.g., prostate and ovary).
- It is possible for an individual to have a genetic variant that has not previously been expressed as an autosomal dominant family history of cancer due to a variety of factors discussed above (refer to question 3).
- It is possible for an individual to have a de novo (new) pathogenic variant. This person would be the first affected member of his or her family but could transmit this trait in the usual autosomal dominant manner to their offspring.
- It is possible for an individual to have pathogenic variants in more than one gene associated with known autosomal dominant inherited cancer predisposition syndromes. In families showing a phenotype suggestive of more than one susceptibility syndrome, identifying such variants helps to clarify the diagnosis and determine the appropriate testing strategy in family members.[46]
Autosomal recessive- Autosomal recessive inheritance refers to an inheritance pattern in which an affected person must be homozygous (i.e., carry two copies of an altered gene, one from each parent). Some well-defined cancer susceptibility syndromes with an autosomal recessive inheritance pattern include Bloom syndrome, ataxia-telangiectasia, MUTYH-associated polyposis, and Fanconi anemia. Autosomal recessive inheritance is characterized by the following:
- Horizontal occurrence (i.e., seen in one generation only [affected siblings in the absence of affected parents]); generally not seen in successive generations.
- Genetic variants must come from both sides of the family (i.e., biparental inheritance).
- Parents are heterozygous carriers; each carries one variant copy of the gene and one functional copy.
- Parents usually do not express the trait or the full syndrome; in some cases, parents may show a mild version of some features.
- In cases of two heterozygous parents, there is a 25% risk of future offspring being affected (homozygous).
Complex- Most cancers, and most familial cancers, appear to have a complex etiology. Within clinical settings, negative or uninformative genetic testing results are common. One possible explanation for these results may be that multiple factors contributed to the development of the observed cancer(s) which are not easy to pinpoint.
- Complex or multifactorial disease inheritance is used to describe conditions caused by genetic and environmental factors. In contrast to mendelian diseases where carrying one specific pathogenic variant is associated with high likelihood for developing the disease, complex/multifactorial diseases are caused by the interaction of genes and environmental factors. Therefore, a single genetic locus is not responsible for the condition. In most cases, the effects of genetic, lifestyle, and environmental factors in aggregate determine a person’s likelihood of being affected with a condition, such as cancer.Clustering of cancer among relatives is common, but teasing out the underlying causes when there is no clear pattern is more difficult. With many common malignancies, such as lung cancer, an excess of cancers in relatives can be seen. These familial aggregations are seen as being due to combinations of exposures to known carcinogens, such as tobacco smoke, and to pathogenic variants in high penetrance genes or alterations in genes with low penetrance that affect the metabolism of the carcinogens in question.[47]The general practitioner is likely to encounter some families with a strong genetic predisposition to cancer and the recognition of cancer susceptibility may have dramatic consequences for a given individual's health and management. Although some high-risk pathogenic variants in major cancer susceptibility genes are consistent with recognizable mendelian inheritance patterns, these syndromes are rare.
- Autosomal dominant inheritance refers to disorders that are expressed in the heterozygote (i.e., the affected person has one copy of a variant allele and one allele that is functioning normally). All the major hereditary breast/ovarian cancer syndromes including BRCA1/BRCA2, Li-Fraumeni, and Cowden, as well as the major hereditary colon cancer syndrome, Lynch syndrome, are inherited in this fashion. Autosomal dominant inheritance is characterized by the following:
- What is the chance of a member of this family developing cancer, if an inherited susceptibility exists?These probabilities vary by syndrome, family, gene, and pathogenic variant, with different variants in the same gene sometimes conferring different cancer risks, or the same variant being associated with different clinical manifestations in different families. These phenomena relate to issues such as penetrance and expressivity that are discussed elsewhere.
- If no recognizable syndrome is present, is there a risk of cancer based on other epidemiological risk factors?A positive family history may sometimes provide risk information in the absence of a specific genetically determined cancer syndrome. For example, the risk associated with having a single affected relative with breast or colorectal cancer can be estimated from data derived from epidemiologic and family studies. Examples of empiric risk estimates of this kind are provided in the PDQ summaries on Genetics of Breast and Gynecologic Cancers and Genetics of Colorectal Cancer.
Methods of quantifying cancer risk
The overarching goal of cancer risk assessment is to individualize cancer risk management recommendations based on personalized risk. Methods to calculate risk utilize health history information and risk factor and family history data often in combination with emerging biologic and genetic/genomic evidence to establish predictions.[48] Multiple methodologies are used to calculate risk, including statistical models, prevalence data from specific populations, penetrance data when a documented pathogenic variant has been identified in a family, mendelian inheritance, and Bayesian analysis. All models have distinct capabilities, weaknesses, and limitations based on the methodology, sample size, and/or population used to create the model. Methods to individually quantify risk encompass two primary areas: the probability of harboring a pathogenic variant in a cancer susceptibility gene and the risk of developing a specific form of cancer.[48]
Risk of harboring a pathogenic variant in a cancer susceptibility gene
The decision to offer genetic testing for cancer susceptibility is complex and can be aided in part by objectively assessing an individual's and/or family's probability of harboring a pathogenic variant.[49] Predicting the probability of harboring a pathogenic variant in a cancer susceptibility gene can be done using several strategies, including empiric data, statistical models, population prevalence data, Mendel’s laws, Bayesian analysis, and specific health information, such as tumor-specific features.[49,50] All of these methods are gene specific or cancer-syndrome specific and are employed only after a thorough assessment has been completed and genetic differential diagnoses have been established.
If a gene or hereditary cancer syndrome is suspected, models specific to that disorder can be used to determine whether genetic testing may be informative. (Refer to the PDQ summaries on the Genetics of Breast and Gynecologic Cancers; Genetics of Colorectal Cancer; or the Genetics of Skin Cancer for more information about cancer syndrome-specific probability models.) The key to using specific models or prevalence data is to apply the model or statistics only in the population best suited for its use. For instance, a model or prevalence data derived from a population study of individuals older than 35 years may not accurately be applied in a population aged 35 years and younger. Care must be taken when interpreting the data obtained from various risk models because they differ with regard to what is actually being estimated. Some models estimate the risk of a pathogenic variant being present in the family; others estimate the risk of a pathogenic variant being present in the individual being counseled. Some models estimate the risk of specific cancers developing in an individual, while others estimate more than one of the data above. (Refer to NCI's Risk Prediction Models website or the disease-specific PDQ cancer genetics summaries for more information about specific cancer risk prediction and pathogenic variant probability models.) Other important considerations include critical family constructs, which can significantly impact model reliability, such as small family size or male-dominated families when the cancer risks are predominately female in origin, adoption, and early deaths from other causes.[42,50] In addition, most models provide gene and/or syndrome-specific probabilities but do not account for the possibility that the personal and/or family history of cancer may be conferred by an as-yet-unidentified cancer susceptibility gene.[43] In the absence of a documented pathogenic variant in the family, critical assessment of the personal and family history is essential in determining the usefulness and limitations of probability estimates used to aid in the decisions regarding indications for genetic testing.[43,49,50]
When a pathogenic variant has been identified in a family and a test report documents that finding, prior probabilities can be ascertained with a greater degree of reliability. In this setting, probabilities can be calculated based on the pattern of inheritance associated with the gene in which the pathogenic variant has been identified. In addition, critical to the application of mendelian inheritance is the consideration of integrating Bayes Theorem, which incorporates other variables, such as current age, into the calculation for a more accurate posterior probability.[1,51] This is especially useful in individuals who have lived to be older than the age at which cancer is likely to develop based on the pathogenic variant identified in their family and therefore have a lower likelihood of harboring the family pathogenic variant when compared with the probability based on their relationship to the carrier in the family.
Even in the case of a documented pathogenic variant on one side of the family, careful assessment and evaluation of the individual’s personal and family history of cancer is essential to rule out cancer risk or suspicion of a cancer susceptibility gene pathogenic variant on the other side of the family (maternal or paternal, as applicable).[52] Segregation of more than one pathogenic variant in a family is possible (e.g., in circumstances in which a cancer syndrome has founder pathogenic variants associated with families of particular ancestral origin).
Risk of developing cancer
Unlike pathogenic variant probability models that predict the likelihood that a given personal and/or family history of cancer could be associated with a pathogenic variant in a specific gene(s), other methods and models can be used to estimate the risk of developing cancer over time. Similar to pathogenic variant probability assessments, cancer risk calculations are also complex and necessitate a detailed health history and family history. In the presence of a documented pathogenic variant, cancer risk estimates can be derived from peer-reviewed penetrance data.[1] Penetrance data are constantly being refined and many genetic variants have variable penetrance because other variables may impact the absolute risk of cancer in any given patient. Modifiers of cancer risk in carriers of pathogenic variants include the variant's effect on the function of the gene/protein (e.g., variant type and position), the contributions of modifier genes, and personal and environmental factors (e.g., the impact of bilateral salpingo-oophorectomy performed for other indications in a woman who harbors a BRCA pathogenic variant).[53] When there is evidence of an inherited susceptibility to cancer but genetic testing has not been performed, analysis of the pedigree can be used to estimate cancer risk. This type of calculation uses the probability the individual harbors a genetic variant and variant-specific penetrance data to calculate cancer risk.[1]
In the absence of evidence of a hereditary cancer syndrome, several methods can be utilized to estimate cancer risk. Relative risk data from studies of specific risk factors provide ratios of observed versus expected cancers associated with a given risk factor. However, utilizing relative risk data for individualized risk assessment can have significant limitations: relative risk calculations will differ based on the type of control group and other study-associated biases, and comparability across studies can vary widely.[51] In addition, relative risks are lifetime ratios and do not provide age-specific calculations, nor can the relative risk be multiplied by population risk to provide an individual's risk estimate.[51,54]
In spite of these limitations, disease-specific cumulative risk estimates are most often employed in clinical settings. These estimates usually provide risk for a given time interval and can be anchored to cumulative risks of other health conditions in a given population (e.g., the 5-year risk by the Gail model).[51,54] Cumulative risk models have limitations that may underestimate or overestimate risk. For example, the Gail model excludes paternal family histories of breast cancer.[50] Furthermore, many of these models were constructed from data derived from predominately Caucasian populations and may have limited validity when used to estimate risk in other ethnicities.[55]
Cumulative risk estimates are best used when evidence of other underlying significant risk factors have been ruled out. Careful evaluation of an individual's personal health and family history can identify other confounding risk factors that may outweigh a risk estimate derived from a cumulative risk model. For example, a woman with a prior biopsy showing lobular carcinoma in situ (LCIS) whose mother was diagnosed with breast cancer at age 65 years has a greater lifetime risk from her history of LCIS than her cumulative lifetime risk of breast cancer based on one first-degree relative.[56,57] In this circumstance, recommendations for cancer risk management would be based on the risk associated with her LCIS. Unfortunately, there is no reliable method for combining all of an individual's relevant risk factors for an accurate absolute cancer risk estimate, nor are individual risk factors additive.
In summary, careful ascertainment and review of personal health and cancer family history are essential adjuncts to the use of prior probability models and cancer risk assessment models to assure that critical elements influencing risk calculations are considered.[49] Influencing factors include the following:
- Differential diagnosis that is consistent with the personal and cancer family history.
- Consideration of factors that influence how informative the family history may be.
- Population that is best suited for the use of the model.
- Tumor-specific features that may be suspicious for an inherited predisposition or modify individual cancer risk predictions.
- Model-specific limitations that can overestimate or underestimate calculations.[43]
References
- Riley BD, Culver JO, Skrzynia C, et al.: Essential elements of genetic cancer risk assessment, counseling, and testing: updated recommendations of the National Society of Genetic Counselors. J Genet Couns 21 (2): 151-61, 2012. [PUBMED Abstract]
- Robson ME, Bradbury AR, Arun B, et al.: American Society of Clinical Oncology Policy Statement Update: Genetic and Genomic Testing for Cancer Susceptibility. J Clin Oncol 33 (31): 3660-7, 2015. [PUBMED Abstract]
- Berliner JL, Fay AM, Cummings SA, et al.: NSGC practice guideline: risk assessment and genetic counseling for hereditary breast and ovarian cancer. J Genet Couns 22 (2): 155-63, 2013. [PUBMED Abstract]
- Lancaster JM, Powell CB, Chen LM, et al.: Society of Gynecologic Oncology statement on risk assessment for inherited gynecologic cancer predispositions. Gynecol Oncol 136 (1): 3-7, 2015. [PUBMED Abstract]
- Committee on Practice Bulletins–Gynecology, Committee on Genetics, Society of Gynecologic Oncology: Practice Bulletin No 182: Hereditary Breast and Ovarian Cancer Syndrome. Obstet Gynecol 130 (3): e110-e126, 2017. [PUBMED Abstract]
- Rimer BK, Schildkraut JM, Lerman C, et al.: Participation in a women's breast cancer risk counseling trial. Who participates? Who declines? High Risk Breast Cancer Consortium. Cancer 77 (11): 2348-55, 1996. [PUBMED Abstract]
- Evans DG, Burnell LD, Hopwood P, et al.: Perception of risk in women with a family history of breast cancer. Br J Cancer 67 (3): 612-4, 1993. [PUBMED Abstract]
- Kash KM, Holland JC, Halper MS, et al.: Psychological distress and surveillance behaviors of women with a family history of breast cancer. J Natl Cancer Inst 84 (1): 24-30, 1992. [PUBMED Abstract]
- Davis S, Stewart S, Bloom J: Increasing the accuracy of perceived breast cancer risk: results from a randomized trial with Cancer Information Service callers. Prev Med 39 (1): 64-73, 2004. [PUBMED Abstract]
- Kelly KM, Shedlosky-Shoemaker R, Porter K, et al.: Cancer family history reporting: impact of method and psychosocial factors. J Genet Couns 16 (3): 373-82, 2007. [PUBMED Abstract]
- Armel SR, McCuaig J, Finch A, et al.: The effectiveness of family history questionnaires in cancer genetic counseling. J Genet Couns 18 (4): 366-78, 2009. [PUBMED Abstract]
- Appleby-Tagoe JH, Foulkes WD, Palma L: Reading between the lines: a comparison of responders and non-responders to a family history questionnaire and implications for cancer genetic counselling. J Genet Couns 21 (2): 273-91, 2012. [PUBMED Abstract]
- Wang C, Gallo RE, Fleisher L, et al.: Literacy assessment of family health history tools for public health prevention. Public Health Genomics 14 (4-5): 222-37, 2011. [PUBMED Abstract]
- Vogel TJ, Stoops K, Bennett RL, et al.: A self-administered family history questionnaire improves identification of women who warrant referral to genetic counseling for hereditary cancer risk. Gynecol Oncol 125 (3): 693-8, 2012. [PUBMED Abstract]
- Tehranifar P, Wu HC, Shriver T, et al.: Validation of family cancer history data in high-risk families: the influence of cancer site, ethnicity, kinship degree, and multiple family reporters. Am J Epidemiol 181 (3): 204-12, 2015. [PUBMED Abstract]
- Bennett RL, Steinhaus KA, Uhrich SB, et al.: Recommendations for standardized human pedigree nomenclature. Pedigree Standardization Task Force of the National Society of Genetic Counselors. Am J Hum Genet 56 (3): 745-52, 1995. [PUBMED Abstract]
- Bennett RL, French KS, Resta RG, et al.: Standardized human pedigree nomenclature: update and assessment of the recommendations of the National Society of Genetic Counselors. J Genet Couns 17 (5): 424-33, 2008. [PUBMED Abstract]
- Lu KH, Wood ME, Daniels M, et al.: American Society of Clinical Oncology Expert Statement: collection and use of a cancer family history for oncology providers. J Clin Oncol 32 (8): 833-40, 2014. [PUBMED Abstract]
- Schneider K: Collection and interpretation of cancer histories. In: Schneider KA: Counseling About Cancer: Strategies for Genetic Counseling. 2nd ed. New York, NY: Wiley-Liss, 2002, pp 129-166.
- Wideroff L, Garceau AO, Greene MH, et al.: Coherence and completeness of population-based family cancer reports. Cancer Epidemiol Biomarkers Prev 19 (3): 799-810, 2010. [PUBMED Abstract]
- Mitchell RJ, Brewster D, Campbell H, et al.: Accuracy of reporting of family history of colorectal cancer. Gut 53 (2): 291-5, 2004. [PUBMED Abstract]
- Schneider KA, DiGianni LM, Patenaude AF, et al.: Accuracy of cancer family histories: comparison of two breast cancer syndromes. Genet Test 8 (3): 222-8, 2004. [PUBMED Abstract]
- Douglas FS, O'Dair LC, Robinson M, et al.: The accuracy of diagnoses as reported in families with cancer: a retrospective study. J Med Genet 36 (4): 309-12, 1999. [PUBMED Abstract]
- Sijmons RH, Boonstra AE, Reefhuis J, et al.: Accuracy of family history of cancer: clinical genetic implications. Eur J Hum Genet 8 (3): 181-6, 2000. [PUBMED Abstract]
- Mai PL, Garceau AO, Graubard BI, et al.: Confirmation of family cancer history reported in a population-based survey. J Natl Cancer Inst 103 (10): 788-97, 2011. [PUBMED Abstract]
- Ozanne EM, O'Connell A, Bouzan C, et al.: Bias in the reporting of family history: implications for clinical care. J Genet Couns 21 (4): 547-56, 2012. [PUBMED Abstract]
- Brennan P, Claber O, Brennan T: Cancer family history triage: a key step in the decision to offer screening and genetic testing. Fam Cancer 12 (3): 497-502, 2013. [PUBMED Abstract]
- Beadles CA, Ryanne Wu R, Himmel T, et al.: Providing patient education: impact on quantity and quality of family health history collection. Fam Cancer 13 (2): 325-32, 2014. [PUBMED Abstract]
- Evans DG, Kerr B, Cade D, et al.: Fictitious breast cancer family history. Lancet 348 (9033): 1034, 1996. [PUBMED Abstract]
- Qureshi N, Wilson B, Santaguida P, et al.: Collection and Use of Cancer Family History in Primary Care. Evidence Report/Technology Assessment No. 159. Rockville,Md: Agency for Healthcare Research and Quality, 2007. AHRQ Pub No. 08-E001.
- Murff HJ, Spigel DR, Syngal S: Does this patient have a family history of cancer? An evidence-based analysis of the accuracy of family cancer history. JAMA 292 (12): 1480-9, 2004. [PUBMED Abstract]
- Hampel H, Bennett RL, Buchanan A, et al.: A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment. Genet Med 17 (1): 70-87, 2015. [PUBMED Abstract]
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Breast and Ovarian. Version 3.2019. Plymouth Meeting, Pa: National Comprehensive Cancer Network, 2019. Available online with free registration. Last accessed January 29, 2019.
- National Comprehensive Cancer Network: NCCN Clinical Practice Guidelines in Oncology: Genetic/Familial High-Risk Assessment: Colorectal. Version 1.2018. Plymouth Meeting, PA: National Comprehensive Cancer Network, 2018. Available online with free registration. Last accessed October 22, 2018.
- Spoto CPE, Gullo I, Carneiro F, et al.: Hereditary gastrointestinal carcinomas and their precursors: An algorithm for genetic testing. Semin Diagn Pathol 35 (3): 170-183, 2018. [PUBMED Abstract]
- Roberts ME, Jackson SA, Susswein LR, et al.: MSH6 and PMS2 germ-line pathogenic variants implicated in Lynch syndrome are associated with breast cancer. Genet Med : , 2018. [PUBMED Abstract]
- Espenschied CR, LaDuca H, Li S, et al.: Multigene Panel Testing Provides a New Perspective on Lynch Syndrome. J Clin Oncol 35 (22): 2568-2575, 2017. [PUBMED Abstract]
- Bougeard G, Renaux-Petel M, Flaman JM, et al.: Revisiting Li-Fraumeni Syndrome From TP53 Mutation Carriers. J Clin Oncol 33 (21): 2345-52, 2015. [PUBMED Abstract]
- Pilarski R, Eng C: Will the real Cowden syndrome please stand up (again)? Expanding mutational and clinical spectra of the PTEN hamartoma tumour syndrome. J Med Genet 41 (5): 323-6, 2004. [PUBMED Abstract]
- Eng C: PTEN Hamartoma Tumor Syndrome (PHTS). In: Pagon RA, Adam MP, Bird TD, et al., eds.: GeneReviews. Seattle, Wash: University of Washington, 1993-2018, pp. Available online. Last accessed December 07, 2018.
- Brandi ML, Gagel RF, Angeli A, et al.: Guidelines for diagnosis and therapy of MEN type 1 and type 2. J Clin Endocrinol Metab 86 (12): 5658-71, 2001. [PUBMED Abstract]
- Weitzel JN, Lagos VI, Cullinane CA, et al.: Limited family structure and BRCA gene mutation status in single cases of breast cancer. JAMA 297 (23): 2587-95, 2007. [PUBMED Abstract]
- Kauff ND, Offit K: Modeling genetic risk of breast cancer. JAMA 297 (23): 2637-9, 2007. [PUBMED Abstract]
- Kramer JL, Velazquez IA, Chen BE, et al.: Prophylactic oophorectomy reduces breast cancer penetrance during prospective, long-term follow-up of BRCA1 mutation carriers. J Clin Oncol 23 (34): 8629-35, 2005. [PUBMED Abstract]
- Harper PS: Practical Genetic Counselling. 3rd ed. London: Wright, 1988.
- Whitworth J, Skytte AB, Sunde L, et al.: Multilocus Inherited Neoplasia Alleles Syndrome: A Case Series and Review. JAMA Oncol 2 (3): 373-9, 2016. [PUBMED Abstract]
- Stratton MR: Exploring the genomes of cancer cells: progress and promise. Science 331 (6024): 1553-8, 2011. [PUBMED Abstract]
- Freedman AN, Seminara D, Gail MH, et al.: Cancer risk prediction models: a workshop on development, evaluation, and application. J Natl Cancer Inst 97 (10): 715-23, 2005. [PUBMED Abstract]
- Lindor NM, Lindor RA, Apicella C, et al.: Predicting BRCA1 and BRCA2 gene mutation carriers: comparison of LAMBDA, BRCAPRO, Myriad II, and modified Couch models. Fam Cancer 6 (4): 473-82, 2007. [PUBMED Abstract]
- Domchek SM, Eisen A, Calzone K, et al.: Application of breast cancer risk prediction models in clinical practice. J Clin Oncol 21 (4): 593-601, 2003. [PUBMED Abstract]
- Offit K, Brown K: Quantitating familial cancer risk: a resource for clinical oncologists. J Clin Oncol 12 (8): 1724-36, 1994. [PUBMED Abstract]
- Apicella C, Andrews L, Hodgson SV, et al.: Log odds of carrying an Ancestral Mutation in BRCA1 or BRCA2 for a Defined personal and family history in an Ashkenazi Jewish woman (LAMBDA). Breast Cancer Res 5 (6): R206-16, 2003. [PUBMED Abstract]
- Chenevix-Trench G, Milne RL, Antoniou AC, et al.: An international initiative to identify genetic modifiers of cancer risk in BRCA1 and BRCA2 mutation carriers: the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA). Breast Cancer Res 9 (2): 104, 2007. [PUBMED Abstract]
- Hoskins KF, Stopfer JE, Calzone KA, et al.: Assessment and counseling for women with a family history of breast cancer. A guide for clinicians. JAMA 273 (7): 577-85, 1995. [PUBMED Abstract]
- Adams-Campbell LL, Makambi KH, Palmer JR, et al.: Diagnostic accuracy of the Gail model in the Black Women's Health Study. Breast J 13 (4): 332-6, 2007 Jul-Aug. [PUBMED Abstract]
- Fisher ER, Land SR, Fisher B, et al.: Pathologic findings from the National Surgical Adjuvant Breast and Bowel Project: twelve-year observations concerning lobular carcinoma in situ. Cancer 100 (2): 238-44, 2004. [PUBMED Abstract]
- Chuba PJ, Hamre MR, Yap J, et al.: Bilateral risk for subsequent breast cancer after lobular carcinoma-in-situ: analysis of surveillance, epidemiology, and end results data. J Clin Oncol 23 (24): 5534-41, 2005. [PUBMED Abstract]
- Emery J, Morris H, Goodchild R, et al.: The GRAIDS Trial: a cluster randomised controlled trial of computer decision support for the management of familial cancer risk in primary care. Br J Cancer 97 (4): 486-93, 2007. [PUBMED Abstract]
Education and Counseling About Risk/Risk Communication
Specific clinical programs for risk management may be offered to persons with an increased genetic risk of cancer. These programs may differ from those offered to persons of average risk in several ways: screening may be initiated at an earlier age or involve shorter screening intervals; screening strategies not in routine use, such as screening for ovarian cancer, may be offered; and interventions to reduce cancer risk, such as risk-reducing surgery, may be offered. Current recommendations are summarized in the PDQ summaries addressing the genetics of specific cancers.
The goal of genetic education and counseling is to help individuals understand their personal risk status, their options for cancer risk management, and to explore feelings regarding their personal risk status. Counseling focuses on obtaining and giving information, promoting autonomous decision making, and facilitating informed consent if genetic testing is pursued.
Optimally, education and counseling about cancer risk includes providing the following information:
- Purpose, strengths, and limitations of cancer risk assessment.
- Basic genetics and patterns of inheritance.
- Genetic basis of cancer.
- Clinical features of relevant hereditary cancer syndromes.
- Evidence of a hereditary cancer syndrome from the consultand's personal and family history.
- Options for clarifying cancer risk, including genetic testing, if indicated.
- Options available for risk management, including data (or lack of data) on the efficacy of different measures for early detection and risk reduction.
- Signs and symptoms of cancer.
When a clinically valid genetic test is available, education and counseling for genetic testing typically includes the following:
- Risk of having a pathogenic variant and patterns of transmission.
- Alternatives to genetic testing.
- Risks, benefits and limitations of genetic testing, including psychological and discriminatory risks.
- Possible test outcomes, including likelihood of uninformative results and identifying variants of uncertain significance.
- Sensitivity of the genetic test, including the techniques utilized to perform the test and their associated limitations.
- Health care management options based on possible test results.
- Implications for children and other family members based on pattern of transmission.
- Dissemination of risk and genetic information to family members.
- Cost associated with testing, counseling, medical management, and options for insurance coverage.
- How genetic information and genetic test results will be recorded in the medical record.
- Specimen storage and reuse, if applicable.
If a second session is held to disclose and interpret genetic test results, education and counseling focuses on the following:
- Interpretation of test results.
- Discussion of further testing that may clarify risk (e.g., large rearrangement testing and testing the other genes based on the patient's differential cancer syndrome list).
- Assessment of the emotional and behavioral responses to genetic test results.
- Recommendations for coping and communication strategies to address issues related to cancer risk.
- Cancer risk management recommendations.
- Risk analysis and dissemination of risk results to family members.
The process of counseling may require more than one visit to address medical, genetic testing, and psychosocial support issues. Additional case-related preparation time is spent before and after the consultation sessions to obtain and review medical records, complete case documentation, seek information about differential diagnoses, identify appropriate laboratories for genetic tests, find patient support groups, research resources, and communicate with or refer to other specialists.[1]
Information about inherited risk of cancer is growing rapidly. Many of the issues discussed in a counseling session may need to be revisited as new information emerges. At the end of the counseling process, individuals are typically reminded of the possibility that future research may provide new options and/or new information on risk. Individuals may be advised to check in with the health care provider periodically to determine whether new information is sufficient to merit an additional counseling session. The obligation of health care providers to recontact individuals when new genetic testing or treatment options are available is controversial, and standards have not been established.
Methods of Risk Presentation
The usage of numerical probabilities to communicate risk may overestimate the level of risk certainty, especially when wide confidence intervals exist to the estimates or when the individual may differ in important ways from the sample on which the risk estimate was derived. Also, numbers are often inadequate for expressing gut-level or emotional aspects of risk. Finally, there are wide variations in individuals’ level of understanding of mathematical concepts (i.e., numeracy). For all the above reasons, conveying risk in multiple ways, both numerically and verbally, with discussion of important caveats, may be a useful strategy to increase risk comprehension. The numerical format that facilitates the best understanding is natural frequencies because frequencies include information concerning the denominator, the reference group to which the individual may refer. In general, logarithmic scales are to be avoided.[2] Additionally, important “contextual” risks may be included with the frequency in order to increase risk comprehension; these may include how the person’s risk compares with those who do not have the risk factor in question and the risks associated with common hazards, such as being in a car accident. Additional suggestions include being consistent in risk formats (do not mix odds and percentages), using the same denominator across risk estimates, avoiding decimal points, including base rate information, and providing more explanation if the risk is less than 1%.
The communication of risk may be numerical, verbal, or visual. Use of multiple strategies may increase comprehension and retention of cancer genetic risk information.[2] Recently, use of visual risk communication strategies has increased (e.g., histograms, pie charts, and Venn diagrams). Visual depictions of risk may be very useful in avoiding problems with comprehension of numbers, but research that confirms this is lacking.[3,4] A study published in 2008 examined the use of two different visual aids to communicate breast cancer risk. Women at an increased risk of breast cancer were randomized to receive feedback via a bar graph alone or a bar graph plus a frequency diagram (i.e., highlighted human figures). Results indicate that overall, there were no differences in improved accuracy of risk perception between the two groups, but among those women who inaccurately perceived very high risk at baseline, the group receiving both visual aids showed greater improvement in accuracy.[5]
Risk Communication
The purpose of risk counseling is to provide individuals with accurate information about their risk, help them understand and interpret their risk, assist them as they use this information to make important health care decisions, and help them make the best possible adjustment to their situation. A systematic review of 28 studies that evaluated communication interventions showed that risk communication benefits users cognitively by increasing their knowledge and understanding of risk perception and does not negatively influence affect (anxiety, cancer-related worry, and depression). Risk communication does not appear to result in a change in use of screening practices and tests. Users received the most benefit from an approach utilizing risk communication along with genetic counseling.[6,7] Perceptions of risk are affected by the manner in which risk information is presented, difficulty understanding probability and heredity,[8,9] and other psychological processes on the part of individuals and providers.[10] Risk may be communicated in many ways (e.g., with numbers, words, or graphics; alone or in relation to other risks; as the probability of having an adverse event; in relative or absolute terms; and through combinations of these methods). The way in which risk information is communicated may affect the individual’s perception of the magnitude of that risk. In general, relative risk estimates (e.g., "You have a threefold increased risk of colorectal cancer") are perceived as less informative than absolute risk (e.g., "You have a 25% risk of colorectal cancer") [11] or risk information presented as a ratio (e.g., 1 in 4).[9] A strong preference for having BRCA1/BRCA2 pathogenic variant risk estimates expressed numerically is reported by women considering testing.[12] Individuals associate widely differing quantitative risks with qualitative descriptors of risk such as “rare” or “common.”[13] More research is needed on the best methods of communicating risk in order to help individuals develop an accurate understanding of their cancer risks.
Communication Strategies
Recent descriptive examination of the process of cancer genetic counseling has found that counseling sessions are predominantly focused on the biomedical teaching required to inform clients of their choices and to put genetic findings in perspective but that attention to psychosocial issues does not detract from teaching goals and may enhance satisfaction in clients undergoing counseling. For instance, one study of communication patterns in 167 pretest counseling sessions for BRCA1 found the sessions to have a predominantly biomedical and educational focus;[14] however, this approach was client focused, with the counselor and client contributing equally to the dialogue. These authors note that there was a marked diversity in counselor styles, both between counselors and within different sessions, for each counselor. The finding of a didactic style was corroborated by other researchers who examined observer-rated content checklists and videotape of 51 counseling sessions for breast cancer susceptibility.[15] Of note, genetic counselors seemed to rely on demographic information and breast cancer history to tailor genetic counseling sessions rather than client’s self-reported expectations or psychosocial factors.[16] Concurrent provision of psychosocial and scientific information may be important in reducing worry in the context of counseling about cancer genetics topics.[17] An increasing appreciation of language choices may contribute to enhanced understanding and reduced anxiety levels in the session; for example, it was noted that patients may appreciate synonymic choices for the word “mutation,” such as “altered gene”.[18] Some authors have published recommendations for cultural tailoring of educational materials for the African-American population, such as a large flip chart, including the use of simple language and pictures, culturally identifiable images (e.g., spiritual symbols and tribal patterns), bright colors, and humor.[19]
Studies have examined novel channels to communicate genetic cancer risk information, deliver psychosocial support, and standardize the genetic counseling process for individuals at increased risk of cancer.[20-27] Much of this literature has attempted to make the genetic counseling session more efficient or to limit the need for the counselor to address basic genetic principles in the session to free up time for the client’s personal and emotional concerns about his or her risk. For example, the receipt of genetic feedback for BRCA1/BRCA2 and mismatch repair gene testing by letter, rather than a face-to-face genetic counseling feedback session, has been investigated.[28] Other modalities include the development of patient assessments or checklists, CD-ROM programs, and interactive computer programs.
Patient assessments or checklists have been developed to facilitate coverage of important areas in the counseling session. One study assessed patients’ psychosocial needs before a hereditary cancer counseling session to determine the assessment’s effect on the session.[29] A total of 246 participants from two familial cancer clinics were randomly assigned to either an intervention arm in which the counselor received assessment results or a usual care control arm. Study results demonstrated that psychosocial concerns were discussed more frequently among intervention participants than among controls, without affecting session length. Moreover, cancer worry and psychological distress were significantly lower for intervention versus control participants 4 weeks after the counseling session.
A second study compared a feedback checklist completed by 197 women attending a high-risk breast clinic prior to the counseling session to convey prior genetic knowledge and misconceptions to aid the counselor in tailoring the session for that client.[22] The use of the feedback checklist led to gains in knowledge from the counseling session but did not reduce genetic counseling time, perhaps because the genetic counselor chose to spend time discussing topics such as psychosocial issues. Use of the checklist did decrease the time spent with the medical oncologist, however. The feedback checklist was compared with a CD-ROM that outlined basic genetic concepts and the benefits and limitations of testing and found that those viewing the CD-ROM spent less time with counselors and were less likely to choose to undergo genetic testing. The CD-ROM did not lead to increased knowledge of genetic concepts, as did use of the checklist.
A prospective study evaluated the effects of a CD-ROM decisional support aid for microsatellite instability (MSI) tumor testing in 239 colorectal cancer patients who met the revised Bethesda criteria but who did not meet the Amsterdam criteria.[30] The study also tested a theoretical model of factors influencing decisional conflict surrounding decisions to pursue MSI tumor testing. Within the study, half of the sample was randomly assigned to receive a brief description of MSI testing within the clinical encounter, and the other half was provided the CD-ROM decisional support aid in addition to the brief description. The CD-ROM and brief description intervention increased knowledge about MSI testing more than the brief description alone did. As a result, decisional conflict decreased because participants felt more prepared to make a decision about the test and had increased perceived benefits of MSI testing.
Other innovative strategies include educational materials and interactive computer technology. In one study, a 13-page color communication aid using a diverse format for conveying risk, including graphic representations and verbal descriptions, was developed.[23] The authors evaluated the influence of the communication aid in 27 women at high risk of a BRCA1/BRCA2 pathogenic variant and compared those who had read the aid to a comparison sample of 107 women who received standard genetic counseling. Improvements in genetic knowledge and accuracy of risk perception were documented in those who had read the aid, with no differences in anxiety or depression between groups. Personalized, interactive electronic materials have also been developed to aid in genetic education and counseling.[24,25] In one study, an interactive computer education program available prior to the genetic counseling session was compared with genetic counseling alone in women undergoing counseling for BRCA1/BRCA2 testing.[25] Use of the computer program prior to genetic counseling reduced face-time with the genetic counselor, particularly for those at lower risk of a BRCA1/BRCA2 pathogenic variant. Many of the counselors reported that their client’s use of the computer program allowed them to be more efficient and to reallocate time spent in the sessions to clients’ unique concerns.
Videoconferencing is an innovative strategy to facilitate genetic counseling sessions with clients who cannot travel to specialized clinic settings. In 37 individuals in the United Kingdom, real-time video conferencing was compared with face-to-face counseling sessions; both methods were found to improve knowledge and reduce anxiety levels.[26] Similarly, teleconferencing sessions, in which the client and genetic specialists were able to talk with each other in real time, were used in rural Maine communities [27] in the pediatric context to convey genetic information and findings for developmental delays and were found to be comparable to in-person consultations in terms of decision-making confidence and satisfaction with the consultations. An Australian study compared the experiences of 106 women who received hereditary breast and ovarian cancer genetic counseling via videoconferencing with the experiences of 89 women who received counseling face to face. Pre- and 1-month postcounseling assessments revealed no significant differences in knowledge gains, satisfaction, cancer-specific anxiety, generalized anxiety, depression, and perceived empathy of the genetic counselor.[31]
References
- Baker DL, Schuette JL, Uhlmann WR, eds.: A Guide to Genetic Counseling. New York, NY: Wiley-Liss, 1998.
- Lipkus IM: Numeric, verbal, and visual formats of conveying health risks: suggested best practices and future recommendations. Med Decis Making 27 (5): 696-713, 2007 Sep-Oct. [PUBMED Abstract]
- Ancker JS, Senathirajah Y, Kukafka R, et al.: Design features of graphs in health risk communication: a systematic review. J Am Med Inform Assoc 13 (6): 608-18, 2006 Nov-Dec. [PUBMED Abstract]
- Schapira MM, Nattinger AB, McHorney CA: Frequency or probability? A qualitative study of risk communication formats used in health care. Med Decis Making 21 (6): 459-67, 2001 Nov-Dec. [PUBMED Abstract]
- Ghosh K, Crawford BJ, Pruthi S, et al.: Frequency format diagram and probability chart for breast cancer risk communication: a prospective, randomized trial. BMC Womens Health 8: 18, 2008. [PUBMED Abstract]
- Edwards A, Gray J, Clarke A, et al.: Interventions to improve risk communication in clinical genetics: systematic review. Patient Educ Couns 71 (1): 4-25, 2008. [PUBMED Abstract]
- Edwards A, Unigwe S, Elwyn G, et al.: Personalised risk communication for informed decision making about entering screening programs. Cochrane Database Syst Rev (1): CD001865, 2003. [PUBMED Abstract]
- Marteau TM, van Duijn M, Ellis I: Effects of genetic screening on perceptions of health: a pilot study. J Med Genet 29 (1): 24-6, 1992. [PUBMED Abstract]
- Hopwood P, Howell A, Lalloo F, et al.: Do women understand the odds? Risk perceptions and recall of risk information in women with a family history of breast cancer. Community Genet 6 (4): 214-23, 2003. [PUBMED Abstract]
- Redelmeier DA, Koehler DJ, Liberman V, et al.: Probability judgement in medicine: discounting unspecified possibilities. Med Decis Making 15 (3): 227-30, 1995 Jul-Sep. [PUBMED Abstract]
- Malenka DJ, Baron JA, Johansen S, et al.: The framing effect of relative and absolute risk. J Gen Intern Med 8 (10): 543-8, 1993. [PUBMED Abstract]
- Winer E, Winer N, Bluman L, et al.: Attitudes and risk perceptions of women with breast cancer considering testing for BRCA1/2. [Abstract] Proceedings of the American Society of Clinical Oncology 16: A1937, 537a, 1997.
- Mazur DJ, Hickam DH: Patients' interpretations of probability terms. J Gen Intern Med 6 (3): 237-40, 1991 May-Jun. [PUBMED Abstract]
- Ellington L, Baty BJ, McDonald J, et al.: Exploring genetic counseling communication patterns: the role of teaching and counseling approaches. J Genet Couns 15 (3): 179-89, 2006. [PUBMED Abstract]
- Pieterse AH, van Dulmen S, van Dijk S, et al.: Risk communication in completed series of breast cancer genetic counseling visits. Genet Med 8 (11): 688-96, 2006. [PUBMED Abstract]
- Lobb EA, Butow PN, Meiser B, et al.: Tailoring communication in consultations with women from high risk breast cancer families. Br J Cancer 87 (5): 502-8, 2002. [PUBMED Abstract]
- Appleton S, Watson M, Rush R, et al.: A randomised controlled trial of a psychoeducational intervention for women at increased risk of breast cancer. Br J Cancer 90 (1): 41-7, 2004. [PUBMED Abstract]
- Hodgson J, Hughes E, Lambert C: "SLANG"--Sensitive Language and the New Genetics--an exploratory study. J Genet Couns 14 (6): 415-21, 2005. [PUBMED Abstract]
- Baty BJ, Kinney AY, Ellis SM: Developing culturally sensitive cancer genetics communication aids for African Americans. Am J Med Genet 118A (2): 146-55, 2003. [PUBMED Abstract]
- Green MJ, Peterson SK, Baker MW, et al.: Effect of a computer-based decision aid on knowledge, perceptions, and intentions about genetic testing for breast cancer susceptibility: a randomized controlled trial. JAMA 292 (4): 442-52, 2004. [PUBMED Abstract]
- Fransen M, Meertens R, Schrander-Stumpel C: Communication and risk presentation in genetic counseling. Development of a checklist. Patient Educ Couns 61 (1): 126-33, 2006. [PUBMED Abstract]
- Wang C, Gonzalez R, Milliron KJ, et al.: Genetic counseling for BRCA1/2: a randomized controlled trial of two strategies to facilitate the education and counseling process. Am J Med Genet A 134 (1): 66-73, 2005. [PUBMED Abstract]
- Lobb EA, Butow PN, Moore A, et al.: Development of a communication aid to facilitate risk communication in consultations with unaffected women from high risk breast cancer families: a pilot study. J Genet Couns 15 (5): 393-405, 2006. [PUBMED Abstract]
- Mackay J, Schulz P, Rubinelli S, et al.: Online patient education and risk assessment: project OPERA from Cancerbackup. Putting inherited breast cancer risk information into context using argumentation theory. Patient Educ Couns 67 (3): 261-6, 2007. [PUBMED Abstract]
- Green MJ, Peterson SK, Baker MW, et al.: Use of an educational computer program before genetic counseling for breast cancer susceptibility: effects on duration and content of counseling sessions. Genet Med 7 (4): 221-9, 2005. [PUBMED Abstract]
- Coelho JJ, Arnold A, Nayler J, et al.: An assessment of the efficacy of cancer genetic counselling using real-time videoconferencing technology (telemedicine) compared to face-to-face consultations. Eur J Cancer 41 (15): 2257-61, 2005. [PUBMED Abstract]
- Lea DH, Johnson JL, Ellingwood S, et al.: Telegenetics in Maine: Successful clinical and educational service delivery model developed from a 3-year pilot project. Genet Med 7 (1): 21-7, 2005. [PUBMED Abstract]
- Voorwinden JS, Jaspers JP, ter Beest JG, et al.: The introduction of a choice to learn pre-symptomatic DNA test results for BRCA or Lynch syndrome either face-to-face or by letter. Clin Genet 81 (5): 421-9, 2012. [PUBMED Abstract]
- Eijzenga W, Aaronson NK, Hahn DE, et al.: Effect of routine assessment of specific psychosocial problems on personalized communication, counselors’ awareness, and distress levels in cancer genetic counseling practice: a randomized controlled trial. J Clin Oncol 32 (27): 2998-3004, 2014. [PUBMED Abstract]
- Hall MJ, Manne SL, Winkel G, et al.: Effects of a decision support intervention on decisional conflict associated with microsatellite instability testing. Cancer Epidemiol Biomarkers Prev 20 (2): 249-54, 2011. [PUBMED Abstract]
- Zilliacus EM, Meiser B, Lobb EA, et al.: Are videoconferenced consultations as effective as face-to-face consultations for hereditary breast and ovarian cancer genetic counseling? Genet Med 13 (11): 933-41, 2011. [PUBMED Abstract]
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