Malignant mesothelioma is a cancerous tumor of the pleura (lining of the lung and chest cavity) or peritoneum (lining of the abdomen) that is almost always caused by sustained exposure to asbestos.

Causes, incidence, and risk factors

Malignant mesothelioma is a diffuse tumor that affects men more frequently than women. Sustained exposure to asbestos is the predominant risk factor. However, smoking dramatically increases risk amongst the asbestos-exposed. The latent period between asbestos exposure and onset of symptoms can be 20 to 50 years or even longer. The median age of diagnosis is 60. The tumor can spread rapidly to involve the pericardium (sac around the heart), mediastinum, and opposite pleura. Progressive pain and shortness of breath can occur. The tumor is usually associated with a pleural effusion . Differentiation of the tumor from other conditions of the pleura and other types of cancer can be difficult, even when experienced pathologists are viewing biopsy samples.

Signs and tests

Chest X-ray

showing tumor and possibly showing

pleural effusion (which may be bloody)

Thoracic CT

Cytology from pleural fluid

Open lung biopsy

Treatment

Results of treatment for malignant mesothelioma have been disappointing. When found in the early stages, surgery may result in cure. Chemotherapy and radiation may help to increase the chance of cure after surgery.

When the disease is too advanced for surgery, chemotherapy or radiation may be used to reduce symptoms. Cure is usually not possible. A 2002 study showed that a chemotherapy regimen of two drugs -- cisplatin and a new drug called pemetrexed -- appears promising in improving survival and decreasing symptoms. Consider participating in a clinical trial (test of new treatments), which may give you additional treatment options. Supportive treatment (such as pain relief and oxygen) may also help to relieve symptoms.

Support groups

The stress of illness can often be helped by joining a support group where members share common experiences and problems. See cancer - support group and lung disease - support group .

Expectations (prognosis)

The median survival time varies from 4 to 18 months in different studies. However, prognosis depends on the stage of the tumor and whether surgical removal of the tumor is an option.

Complications

Rapid spread of the tumor to other organs is a complication.

Calling your health care provider

Call for an appointment with your health care provider if symptoms are suggestive of malignant mesothelioma.

Prevention

Avoid exposure to asbestos. Avoid smoking, particularly if you have been exposed to asbestos.