Mesothelioma Cancer Mesothelioma is a rare, aggressive form of cancer that develops in the lining of the lungs, abdomen, or heart. Caused by asbestos, mesothelioma has no known cure and has a very poor prognosis. According to a 2017 report by the Centers for Disease Control, 2,400 – 2,800 people are diagnosed with mesothelioma in the United States each year. People who have worked with or been exposed to asbestos have the highest risk of developing mesothelioma. After being exposed to asbestos, mesothelioma symptoms can take 20 – 50 years to appear. The life expectancy for mesothelioma patients is poor, as there is no cure for the disease. The stage of the disease, cell type, and location of the tumor(s) are the most important factors for a patient’s survival. Factors such as the patient’s overall health, age, and whether the cancer has spread also impact prognosis.