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Pleural MesotheliomaPleural mesothelioma is an aggressive form of cancer that originates in the mesothelial
cells lining the pleura, a membrane that covers the lungs and lines the chest cavity. Approximately 75% of all mesotheliomas diagnosed are pleural
mesotheliomas. Pleural mesothelioma is most commonly unilateral (on one side of the chest), and occurs most often in men age 60-80 with a history of
asbestos exposure, often decades prior to diagnosis.
When pleural mesothelioma begins, it appears as a series of small white nodules which
become diffuse, or widespread on the pleural surface. Gradually, these nodules begin to grow together and thicken, forming a “rind” that encases
the lung and extends into the fissures or grooves of the pleura and the diaphragm. The tumor spreads by direct invasion of surrounding tissue,
inwardly compressing the lung, and outwardly invading the chest wall and ribs.
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SymptomsThe most common symptom for pleural mesothelioma patients is chest pain. But, the pain
often is not associated directly with the lung pleura and often appears in the shoulder or upper abdomen. Shortness of breath, called dyspnea, is also
a symptom. Cough, weight loss and anorexia are present in some patients, but are less common. Finally, the rapid growth of the pleural mesothelioma
cancer tumors enlarges the pleural space, causing it to fill with fluid, which leads to the discomfort or pain associated with first detection of the disease.
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DiagnosisOn initial examination by a doctor, 80% to 95% of patients show pleural effusion on x-ray, the remaining percentage
show little or no fluid. At first, the fluid is free-flowing, and is similar in appearance to that seen in other benign causes or in congestive heart failure,
and because of this, these other possibilities are the first to be ruled out in the diagnostic process. Later, the effusion becomes “loculated”, or contained
within a boundary in the pleural space, where the fluid does not move.
CT scans are more definitive, and may show not only the effusion, but the presence
of pleural masses as well as the size certain lymph nodes; MRI is more sensitive in determining chest wall invasion and spread of disease through the diaphragm;
PET may help in staging the disease for possible surgical resection by ruling out extension to the contralateral (opposite) lung or to other distant sites.
Analysis of pleural fluid yields a confirmed diagnosis in a relatively small percentage of patients, and needle biopsy offers only slightly better results. Today,
the procedure of choice is the VATS (video-assisted thoracoscopy) procedure, which has a diagnostic yield of >95%, and allows for pleural biopsy, drainage of
fluid and pleurodesis. VATS also ensures adequate tissue samples to facilitate a definitive diagnosis.
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TreatmentBased on a number of factors, several treatment options may be available including surgery, chemotherapy, radiotherapy
(or combinations of all three, known as trimodal therapy), clinical trials, gene therapy, immunotherapy, etc. Once a diagnosis is reached, it is important that
all possible options are discussed by the appropriate doctors, the patient and their family. Although pleural mesothelioma continues to be a difficult cancer to
treat, more awareness of the disease, new and better diagnostics, and more successful treatment regimens help to improve its outlook.
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