Mesothelioma is a type of cancer that many people mistakenly assume is lung cancer, but is more complex than that and doesn't always affect the lungs. It's actually a cancer that affects the cells in what's called the mesothelium, which is the lining that surrounds the internal organs of the body. The only known cause of this disease is exposure to asbestos, which is a naturally occurring mineral that has been widely used in things like building materials and manufacturing materials like insulation and many vehicle parts like brake pads. Asbestos contains long, thin fibers that don't break down in the body so when they're inhaled or ingested they stay in place and can eventually cause mesothelioma.
Mesothelioma is actually a very rare type of cancer that typically affects people who worked in industries where their exposure to asbestos is high such as in industrial labor and manufacturing. For years, workers didn't know they were exposed to such a dangerous substance because it takes many years for the asbestos to actually cause disease. Asbestos was used mostly prior to the 1970s and once the danger of its use became clear it was replaced with other materials in many applications. It can stay dormant inside the body for 10 years or more before any symptoms appear. Now, asbestos removal is big business and has to be done by highly trained and well protected workers.
Most people exposed to asbestos in things like their home insulation are not at high risk because asbestos naturally occurs in the air we all breathe. It's the repeated inhalation of high concentrations of asbestos such as has been done by industrial workers that typically causes the disease.
Pleural mesothelioma, which affects the lung lining, is the most common and accounts for about 70% of all mesothelioma cases. But there are also two other types known as peritoneal mesothelioma and pericardial mesothelioma. Peritoneal mesothelioma is a cancer of the lining of the abdominal cavity while pericardial mesothelioma is a cancer of the pericardium which is the lining of the heart.
Not all mesothelioma is malignant. There is a benign form of the disease. Often, this is a precursor to malignant mesothelioma, however, and even in its benign form, the disease can cause impaired lung function and difficulty breathing. While malignant mesothelioma is always fatal, there have been a few cases of people living for several years with the disease. In most cases, the prognosis is far less optimistic than that and death occurs within a year of diagnosis because it's an aggressive cancer that spreads rapidly beyond the mesothelium. Pleural mesothelioma can very quickly spread to the heart, the stomach and the chest wall from the lining of the lungs.
If the disease is caught early enough, particularly if it's pleural mesothelioma, the cancer can be surgically removed and the life expectancy may be longer. Peritoneal and pericardial mesothelioma typically don't have a surgical option. Most treatment for all types of mesothelioma involves chemotherapy and radiation to make the patient more comfortable and possibly slow the progression of the cancer.