Mesothelioma Causes

The only known cause of mesothelioma is exposure to asbestos. While a few alternative causes have been posited, nothing besides exposure to asbestos has been proven to cause mesothelioma.

Individual asbestos fibers are actually microscopic in size. When these are released into the air through the use of asbestos products, countless billions of asbestos fibers can be both breathed in and swallowed by anyone in close proximity to the work. Many of those tiny fibers that are breathed in will make their way into the smallest airways of the lungs so they cannot be breathed or coughed out. Once the fibers are lodged in the lungs, the body's various defense mechanisms try to break them down or remove them. Asbestos fibers, however, are particularly durable (which is one of the reasons asbestos was so widely used in industry and construction for years). As a result, the body cannot process these fibers, and the surrounding tissue grows irritated, inflamed and scarred. When this scarring of the lung tissue becomes excessive, it can interfere with normal breathing. This is called asbestosis.

The asbestos fibers which have made their way to the lungs can also penetrate through the lung tissue to settle in the pleura (the lining of the lung). After many years, these can cause mesothelioma to develop.

Many of the asbestos fibers that are swallowed will become lodged in the digestive system. Some of these then penetrate into the peritoneum (the lining of the abdominal cavity), and many years later these asbestos fibers can cause peritoneal mesothelioma to develop.

While the likelihood of developing mesothelioma increases with heavier exposure to asbestos, someone who has had only minimal exposure to asbestos can also develop mesothelioma. In fact, one 1999 NIOSH (National Institute for Occupational Safety and Health, part of the Center for Disease Control) study found that the second most common occupation listed for victims of mesothelioma was housewife/homemaker. Such household exposure to asbestos usually occurs as a result of someone unknowingly bringing home asbestos to which they were exposed in the workplace on their clothes and in their hair.

Similarly, mesothelioma can develop in people incidentally exposed on the job, not just in those who worked directly with asbestos. People with no obvious direct contact with asbestos, those who merely lived or worked in close proximity to sites where asbestos was widely used, can also develop the disease.

Still, mesothelioma is a relatively rare disease, and, in fact, the majority of people who experienced even substantial exposure to asbestos in their lifetimes will never develop mesothelioma. Click here to learn more about asbestos and exposure to asbestos.

Smoking does not cause mesothelioma. There is no evidence at all that smoking increases a person's risk of developing mesothelioma. Mesothelioma is not a form of lung cancer, but is a cancer of the pleura, a distinct organ.

There have been some studies that suggest that radiation exposure might contribute to some mesotheliomas. Most experts believe that if this is proven true at all, it would only be in extremely rare cases.