Mesothelioma is a rare form of cancer that involves the mesothelium, or cells that line an organ, usually the lungs, abdominal organs, and heart. The most common form of mesothelioma is pleural mesothelioma, where malignant tumors form on the pleura, the sac that lines the chest cavity and protects the lungs. Other forms of mesothelioma affect the peritoneum (abdominal cavity lining) and the pericardium (lining around the heart).
- Mesothelioma is usually caused by asbestos exposure; 70-80% of all cases reported had workplace exposure. Asbestos is a fibrous mineral known to be carcinogenic. People who are exposed to asbestos fibers for just a short period of time (few weeks) or even to a small amount may be at risk. In particular, people working with asbestos and their family members or those who live with them are more likely to develop mesothelioma.
- Mesothelioma is uncommon, though no longer rare. In 2004, the age-adjusted incidence rate for it was 1.1 per 100,000 persons. Though low, this rate has increased 84% since 1977.
- There are about 2,000 to 3,000 new cases of mesothelioma diagnosed in the US each year.
- Men are affected by mesothelioma five times as often as women. The disease rarely appears in those under 55 years of age. Three quarters of those with mesothelioma are over 65 years of age.
- There is a long latency period between initial exposure to asbestos and the development of malignant tumors, 35-50 years may elapse before the onset of symptoms.
- The early symptoms of mesothelioma can resemble pneumonia, including shortness of breath, difficulty breathing, persistent cough, and chest and abdominal pain. Often, there is fluid buildup between the pleura and chest cavity (called pleural effusions), which leads to dyspnea (shortness of breath) and sometimes pain. Some people may not have any symptoms.
- Treatment for mesothelioma can include surgery to remove the tumors, chemotherapy, radiation, or a combination of the three. A healthcare provider and the patient will determine which is best.
- By the time of diagnosis mesothelioma is usually advanced. Because of this the average survival time is only about one year. Relative 5-year survival rates are approximately 10%, though this rate is slowly improving.