Pleural mesothelioma induced by Libby, MT, vermiculite

Pleural mesothelioma is a cancer of the cells that make up the pleura, or lining around the outside of the lungs and inside the ribs. It is an extremely rare disease with an incidence rate of one new case per 100,000 people per year, or about 2,000 to 3,000 new cases per year in the United States. The incidence rate of lung cancer in the United States, by comparison, is about 65 times greater.

The primary factor associated with mesothelioma is previous exposure to asbestos fibers. Amphibole fibers, such as those associated with Libby vermiculite, are thought to be more potent than serpentine fibers, with regard to inducing mesothelioma.

Mesothelioma is a terminal disease. Fewer than half of the patients survive longer than seven months after diagnosis.

In some cases, pleural mesothelioma has occurred in people with no known asbestos exposure. There is likely to be a baseline incidence of mesothelioma around the world that is not attributable to asbestos exposure, just as there may be other factors that contribute to inducing mesothelioma.

Courtesy of the Washington Department of Health