Pleural mesothelioma is the most prevalent of all types of mesothelioma. It affects the soft tissue surrounding the lungs known as the pleura or pleural membrane. Mesothelioma tumors can develop in multiple locations throughout the body, but they originate from the pleura in approximately 75 percent of all cases. In each case, cancer forms in the mesothelium, a tissue membrane that protects various organs and body cavities.
Pleural mesothelioma is typically caused by occupational exposure to airborne asbestos fibers. Because this exposure is frequently in male-dominated industries, around 80 percent of all pleural mesothelioma patients are men. Once inhaled into the lungs, needle-like asbestos fibers migrate to the pleural membrane, where the body cannot easily get rid of them. Fibers irritate the pleura, which can result in chronic inflammation and scarring. Infrequently, this causes pleural mesothelioma.
Over an extended period of time – usually three or more decades – asbestos triggers genetic changes in the pleural cells. If the cells become cancerous, they begin to divide uncontrollably, forming tumors that reduce lung capacity and generate excess fluid buildup between the pleural layers.
The overall outlook for pleural mesothelioma patients is poor. This is because symptoms do not usually arise until more advanced stages of cancer where curative surgery is no longer an option. However, an early diagnosis facilitates the most effective treatment options, potentially improving a patient's outlook and life expectancy.
The pleural lining is composed of two layers that provide protection and support for the lungs and other vital structures of the chest. It also produces a lubricating fluid for the cavity between the two layers to aid the expansion and contraction of the lungs as we breathe. The outer layer, the parietal pleura, lines the entire chest cavity. The inner layer, or visceral layer, covers the lungs.
It is not uncommon for mesothelioma to affect both layers of the pleura. Pleural mesothelioma generally develops in one layer of the pleura and rapidly invades nearby locations such as the diaphragm, chest wall or lung. If the cancer reaches the lymph nodes, it can metastasize, or spread, to distant locations in the body.
Although someone in a later stage of pleural mesothelioma experiences weight loss and fatigue, less than 30 percent of patients experience these symptoms before a diagnosis or during an early stage of the disease. During an initial consultation with their doctor, more than 60 percent of patients experience chest pain and breathlessness related to pleural effusion.
Learn more about pleural mesothelioma symptoms
X-rays or CT-Scans are often used to diagnose pleural mesothelioma.A pleural mesothelioma diagnosis can be made partly on the basis of symptoms, but additional diagnostic tests are often needed to confirm the presence of cancer. To achieve the best treatment options and patient outlook, an early diagnosis is crucial. Following a medical and occupational history review and a physical examination, patients typically undergo imaging tests that identify potentially cancerous tumors. Conventional chest X-rays can reveal pleural effusions and pleural-based masses in some cases, but CT scans provide more advanced images that often reveal evidence of asbestos exposure.
With the introduction of the PET scan in the early 1960s, doctors could better distinguish between benign (non-cancerous) and malignant pleural growths. Additionally, PET scans can detect signs of cancerous spread to the lymph nodes that CT scans often miss, a benefit that is particularly useful for mesothelioma staging. A promising combination of both technologies, known as PET-CT imaging, emerged in 2000. Some experts contend that a PET-CT scan can more accurately predict a patient’s response to chemotherapy than PET and CT scans given alone, but further studies must be done to confirm this with certainty.
Cytologies and biopses help diagnose mesothelioma with higher confidence.While recent advances in imaging have markedly improved the diagnostic process, more invasive procedures are usually needed to diagnose mesothelioma with a high level of confidence. One such procedure is thoracentesis, in which a hollow needle is inserted into the lungs to collect pleural fluid. Using cytologic analysis to inspect the cell samples, doctors look for biomarkers that indicate the presence of cancer, such as epithelial membrane antigen (EMA), calretinin and WT1. Experienced physicians can use cytologic analysis to make an accurate diagnosis in 80 percent of mesothelioma cases.
Sometimes, however, results are inconclusive or pleural fluid is absent entirely. In these cases, doctors perform biopsies to collect pleural tissue samples. Color stains are added to the samples to help doctors visualize cellular structures. One popular biopsy method is fine needle aspiration, but researchers have found that thoracoscopy is far more likely to yield positive results. A thoracoscopic biopsy produces an accurate diagnosis in 98 percent of mesothelioma patients. The current gold standard for diagnosing pleural mesothelioma involves the examination of stained tissue samples under an electron microscope. If a series of tests or biopsies can confirm the presence of mesothelioma, doctors develop a treatment plan based on the results.
Learn more about pleural mesothelioma diagnosis
Surgery continues to serve as a primary treatment option for pleural mesothelioma patients. One common procedure is pleurectomy/decortication (P/D), which involves surgical removal of the tumor and affected pleura. A more aggressive surgical option, extrapleural pneumonectomy (EPP) aims to safely remove an entire lung, the diaphragm and the pericardium, a protective membrane that lines the heart. Only a fraction of patients have lung function adequate enough to qualify for EPP, and one large, multi-facility analysis found that P/D offers better outcomes than EPP with fewer risks.
One of the most common palliative mesothelioma treatments is chemotherapy, which uses one or more drugs to kill cancer cells and decrease the size of tumors. While recent advancements have improved patient responses to chemotherapy, success rates have been low overall. Roughly 15 to 20 percent of mesothelioma patients will experience a notable reduction in tumor size after chemotherapy.
However, mesothelioma clinical trials combining several chemotherapy drugs in one treatment have demonstrated great potential. One multicenter phase 3 study, for example, found that a combination of pemetrexed and cisplatin prolonged patients’ overall median survival by 2.8 months compared to patients treated with cisplatin alone. 41 percent of patients treated with a pemetrexed/cisplatin regimen experienced tumor shrinkage of at least 50 percent. While a combination of chemotherapy drugs that cures pleural mesothelioma has yet to be discovered, this is a primary goal of countless researchers currently involved in clinical trials.
Pleural mesothelioma often resists radiation therapy. In this treatment, doctors administer targeted radiation that destroys cancer cells and decreases tumor size. Although it is a poor curative option, radiation therapy can be quite effective for managing symptoms like chest pain. One of the most successful radiotherapy techniques is called intensity-modulated radiotherapy. Usually given to patients in low-dose intervals after a radical surgery like EPP, this technique prevents cancer recurrence in many cases. While effective at preventing the cancer from returning to areas where radiation is administered, spread to distant sites remains a challenge.
While there is no universally accepted course of treatment for pleural mesothelioma, the majority of experts agree that survival can be greatly improved when several treatments are combined. This is known as multimodal therapy, and researchers constantly experiment with surgery, chemotherapy and radiation therapy to uncover the most effective combination and timing for these treatments. In one example of a multimodal pleural mesothelioma treatment, doctors first perform extrapleural pneumonectomy surgery. Radiation therapy is then administered to reduce the risk of local cancer recurrence, and distant spread is prevented with chemotherapy.
Learn more about pleural mesothelioma treatments
After the diagnostic process, doctors will analyze their mesothelioma patient’s clinical data to predict the expected course and outcome for the disease. This prediction is known as the patient’s prognosis.
Past studies indicate that average survival ranges from four to 18 months, but many factors can significantly affect the prognosis of pleural mesothelioma patients. The most substantial factors include the current stage of disease and the overall health of the patient. Staging is a system doctors use to describe how far the mesothelioma has advanced, so diagnosis at an early stage offers a better prognosis. And patients in good health who can still perform normal daily tasks tend to respond better to the demands of treatment.
Other important prognostic factors include the patient’s age, sex and smoking history. Survival is generally better for female patients, non-smokers and patients younger than 55. The cancer’s histology, or the cellular structure of the tumor, can also strongly influence prognosis. Accounting for 50 to 70 percent of all cases, a subtype known as epithelial mesothelioma offers the most hopeful prognosis. Patients with epithelial mesothelioma respond best to treatment, and other subtypes like sarcomatoid and mixed mesothelioma are associated with poorer survival.
Providing mesothelioma patients with an accurate prognosis can be a challenging task for doctors. Not only is pleural mesothelioma a rare disease, but it is also uncommon for patients to be diagnosed at an early stage. Because most patients don’t qualify for surgery and an operation is required for accurate staging, survival data for stage I and stage II is limited.
Overall, around 40 percent of pleural mesothelioma patients survive one year after a diagnosis. Approximately 20 percent survive for two or more years, and 10 percent will be alive five years later. It is important, however, to understand that these statistics are drawn from large samples of patients. Each individual case is unique, so survival statistics should only serve as general guidelines.
Patients can work with the nation’s top mesothelioma specialists to improve their prognosis and discuss treatment options to extend life expectancy. Many mesothelioma survivors have turned to a dynamic treatment plan that unites traditional and alternative medicine to boost prognosis.
(http://www.asbestos.com)
Pleural mesothelioma is typically caused by occupational exposure to airborne asbestos fibers. Because this exposure is frequently in male-dominated industries, around 80 percent of all pleural mesothelioma patients are men. Once inhaled into the lungs, needle-like asbestos fibers migrate to the pleural membrane, where the body cannot easily get rid of them. Fibers irritate the pleura, which can result in chronic inflammation and scarring. Infrequently, this causes pleural mesothelioma.
Over an extended period of time – usually three or more decades – asbestos triggers genetic changes in the pleural cells. If the cells become cancerous, they begin to divide uncontrollably, forming tumors that reduce lung capacity and generate excess fluid buildup between the pleural layers.
The overall outlook for pleural mesothelioma patients is poor. This is because symptoms do not usually arise until more advanced stages of cancer where curative surgery is no longer an option. However, an early diagnosis facilitates the most effective treatment options, potentially improving a patient's outlook and life expectancy.
The Anatomy and Function of the Pleura
The pleural lining is composed of two layers that provide protection and support for the lungs and other vital structures of the chest. It also produces a lubricating fluid for the cavity between the two layers to aid the expansion and contraction of the lungs as we breathe. The outer layer, the parietal pleura, lines the entire chest cavity. The inner layer, or visceral layer, covers the lungs. It is not uncommon for mesothelioma to affect both layers of the pleura. Pleural mesothelioma generally develops in one layer of the pleura and rapidly invades nearby locations such as the diaphragm, chest wall or lung. If the cancer reaches the lymph nodes, it can metastasize, or spread, to distant locations in the body.
Pleural Mesothelioma Symptoms
When trapped asbestos fibers cause healthy pleural cells to become cancerous, tumors form and the pleural membrane slowly thickens. The thickening can cause pleural effusion, an excess buildup of fluid in the space between the pleural layers. This fluid puts pressure on the lungs, resulting in chest pain and the impairment of normal breathing. These complications are largely responsible for the symptoms of pleural mesothelioma, which include:- Persistent dry or raspy cough
- Coughing up blood (hemoptysis)
- Shortness of breath (dyspnea)
- Pain in the lower back or rib area
- Painful breathing
- Development of lumps under the skin on the chest
- Difficulty with swallowing (dysphagia)
- Night sweats or fever
- Unexplained weight loss
- Fatigue
Learn more about pleural mesothelioma symptoms
Pleural Mesothelioma Diagnosis
As with other types of the disease, pleural mesothelioma can be difficult to diagnose, even for specialists. Symptoms usually do not arise until long after an initial exposure to asbestos. And because many respiratory conditions provoke similar symptoms, pleural mesothelioma is often mistaken for less-threatening diseases like influenza and pneumonia. Further, it is challenging for doctors to distinguish between pleural mesothelioma and adenocarcinoma, a common form of lung cancer.Diagnostic Imaging
X-rays or CT-Scans are often used to diagnose pleural mesothelioma.With the introduction of the PET scan in the early 1960s, doctors could better distinguish between benign (non-cancerous) and malignant pleural growths. Additionally, PET scans can detect signs of cancerous spread to the lymph nodes that CT scans often miss, a benefit that is particularly useful for mesothelioma staging. A promising combination of both technologies, known as PET-CT imaging, emerged in 2000. Some experts contend that a PET-CT scan can more accurately predict a patient’s response to chemotherapy than PET and CT scans given alone, but further studies must be done to confirm this with certainty.
Cytology and Biopsies
Cytologies and biopses help diagnose mesothelioma with higher confidence.Sometimes, however, results are inconclusive or pleural fluid is absent entirely. In these cases, doctors perform biopsies to collect pleural tissue samples. Color stains are added to the samples to help doctors visualize cellular structures. One popular biopsy method is fine needle aspiration, but researchers have found that thoracoscopy is far more likely to yield positive results. A thoracoscopic biopsy produces an accurate diagnosis in 98 percent of mesothelioma patients. The current gold standard for diagnosing pleural mesothelioma involves the examination of stained tissue samples under an electron microscope. If a series of tests or biopsies can confirm the presence of mesothelioma, doctors develop a treatment plan based on the results.
Learn more about pleural mesothelioma diagnosis
Pleural Mesothelioma Treatment
Historically, doctors have managed pleural mesothelioma with traditional cancer treatments like surgery, chemotherapy and radiation therapy. Depending on how far the patient’s mesothelioma has progressed, these therapies can be either curative or palliative. Although pleural mesothelioma patients are rarely diagnosed early enough to qualify for curative surgery, many palliative treatments exist that can alleviate painful symptoms, improve quality of life and significantly extend survival. Researchers are also evaluating several alternative treatments like immunotherapy and gene therapy, which once perfected could one day become standard mesothelioma therapies.Surgery
Chemotherapy
However, mesothelioma clinical trials combining several chemotherapy drugs in one treatment have demonstrated great potential. One multicenter phase 3 study, for example, found that a combination of pemetrexed and cisplatin prolonged patients’ overall median survival by 2.8 months compared to patients treated with cisplatin alone. 41 percent of patients treated with a pemetrexed/cisplatin regimen experienced tumor shrinkage of at least 50 percent. While a combination of chemotherapy drugs that cures pleural mesothelioma has yet to be discovered, this is a primary goal of countless researchers currently involved in clinical trials.
Radiation Therapy
Multimodal Therapies
Learn more about pleural mesothelioma treatments
Pleural Mesothelioma Prognosis
After the diagnostic process, doctors will analyze their mesothelioma patient’s clinical data to predict the expected course and outcome for the disease. This prediction is known as the patient’s prognosis.Past studies indicate that average survival ranges from four to 18 months, but many factors can significantly affect the prognosis of pleural mesothelioma patients. The most substantial factors include the current stage of disease and the overall health of the patient. Staging is a system doctors use to describe how far the mesothelioma has advanced, so diagnosis at an early stage offers a better prognosis. And patients in good health who can still perform normal daily tasks tend to respond better to the demands of treatment.
Other important prognostic factors include the patient’s age, sex and smoking history. Survival is generally better for female patients, non-smokers and patients younger than 55. The cancer’s histology, or the cellular structure of the tumor, can also strongly influence prognosis. Accounting for 50 to 70 percent of all cases, a subtype known as epithelial mesothelioma offers the most hopeful prognosis. Patients with epithelial mesothelioma respond best to treatment, and other subtypes like sarcomatoid and mixed mesothelioma are associated with poorer survival.
Providing mesothelioma patients with an accurate prognosis can be a challenging task for doctors. Not only is pleural mesothelioma a rare disease, but it is also uncommon for patients to be diagnosed at an early stage. Because most patients don’t qualify for surgery and an operation is required for accurate staging, survival data for stage I and stage II is limited.
Overall, around 40 percent of pleural mesothelioma patients survive one year after a diagnosis. Approximately 20 percent survive for two or more years, and 10 percent will be alive five years later. It is important, however, to understand that these statistics are drawn from large samples of patients. Each individual case is unique, so survival statistics should only serve as general guidelines.
Patients can work with the nation’s top mesothelioma specialists to improve their prognosis and discuss treatment options to extend life expectancy. Many mesothelioma survivors have turned to a dynamic treatment plan that unites traditional and alternative medicine to boost prognosis.
(http://www.asbestos.com)
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