What is malignant mesothelioma?
Malignant mesothelioma is cancer of the mesothelium. The mesothelium is a membrane that covers and protects most of the internal organs of the body. In persons with mesothelioma, the cells of the mesothelium become abnormal and divide without control or order. They can invade and damage nearby tissues and organs. They can also metastasize (spread) to other areas of the body.

What is the cause of malignant mesothelioma?
Asbestos exposure is the cause of mesothelioma in virtually all cases. Smoking does not appear to increase a person’s risk of mesothelioma.

What is meant by the term “asbestos exposure?”
Asbestos exposure occurs when a person inhales or swallows asbestos fibers. Asbestos is a mineral that has been used in many industrial and consumer products. Workers who help manufacture or work with asbestos products may inhale or swallow asbestos fibers. Fibers may also be brought home on the clothing of these workers, exposing their family members to asbestos. Homeowners who renovate older houses containing asbestos products may also be exposed to asbestos. For more information on asbestos, see our Frequently asked Questions About Asbestos.

How common is malignant mesothelioma?
It has been estimated that about 3,000 new cases are diagnosed each year.

What is the expected outcome for a patient diagnosed with mesothelioma?
If the disease is detected very early, there is a possibility of removing the diseased tissue surgically. There is a five-year survival rate among mesothelioma sufferers of about 10%. However, the average survival time varies from 4 to 18 months after diagnosis. When the disease is too advanced for surgery, chemotherapy or radiation may be used to reduce symptoms, but a cure is usually not possible.

Are any new treatments for mesothelioma being studied?
Yes. The National Cancer Institute is sponsoring clinical trials that are designed to find new treatments and better ways to use current treatments. Before any new treatment can be recommended for general use, doctors conduct clinical trials to find out if the treatment is safe and effective against the disease. People interested in taking part in a clinical trial should talk with their doctor. Information about clinical trials is available from the Cancer Information Service at 1-800-4-CANCER. Patients also have the option of searching the Internet for clinical trials at www.clinicaltrials.gov.

What is benign mesothelioma?
Benign or fibrous mesothelioma, which is extremely rare, is a noncancerous tumor of the pleura (lining of the lungs). It can make breathing painful and difficult. It can often be treated successfully with surgery. Benign mesothelioma is not thought to be related to asbestos exposure.