Mesothelioma is a rare cancer of the tissue that lines the body's internal organs. About 2,000 new cases are diagnosed each year in the US. Of these, 75 percent of cases affect the sac that protects the lungs, called the pleura. This is known as pleural mesothelioma. In about ten to 20 percent of cases, mesothelioma may affect the tissue that surrounds abdominal organs, called the peritoneal membrane, causing what is known as peritoneal mesothelioma.
Exposure to asbestos is the primary risk factor for this disease. Following asbestos exposure, the time to development of mesothelioma may be two to four decades. Due to occupational exposure, mesothelioma is about three times more common in men, than in women. Because the number of cases rises with age, there are about ten times more cases in men over age 64 than in men in their 30s.
There are three main pathologic subtypes of mesothelioma: epithelial, which accounts for 50 to 70 percent of cases; sarcoma, which comprises seven to 20 percent of cases; and mixed type, which accounts for 20 to 35 percent of cases and contains both epithelial and sarcomatous cell types.
Mesothelioma is a serious disease, which, at the current time, has a very low rate of long-term survival. However, if diagnosed early, treatments are available that will significantly extend life. New therapies and approaches continue to be tested and developed through the use of clinical trials.
