Mayo Clinic Q&A: Asbestos exposure most significant risk factor for mesothelioma

DEAR MAYO CLINIC: What causes mesothelioma, and how is it different from lung cancer? Are there any treatments or ways to slow its progression?

ANSWER: Mesothelioma is a rare type of cancer, with about 3,000 new cases reported each year in the United States. It is much less common than lung cancer. Unlike lung cancer, mesothelioma does not start within the lung tissue. It arises from the mesothelium that forms the outside lining of the lung, also called the pleura; however, mesothelioma may spread into the lungs.

Rarely, it can also arise from the lining of the abdominal cavity or other internal organs. The exact cause is unclear, but there appears to be a strong association...