Key Facts:

  • Mesothelioma is a rare type of cancer that occurs in the lining of the lungs (pleura) and less commonly the lining of the abdomen (peritoneum).
  • Eight out of 10 people with mesothelioma report asbestos exposure, which is why it is considered the biggest risk factor of developing the disease.
  • There are approximately 3,000 new cases of mesothelioma every year in the United States. The number of cases has been declining since the early 1990s, most likely due to a reduction in workplace exposure to asbestos.
  • Although treatments for mesothelioma are improving, it remains an aggressive and deadly cancer.

How Mesothelioma Affects Your Body

Mesothelioma, like all cancers, starts when a cell’s DNA experiences changes (mutations) that cause the cell to receive the wrong information and multiply unchecked. This out of control cell growth results in a tumor (mass).

Scientists do not know for sure what causes mesothelioma, however, researchers have identified factors that are proven to increase the risk for developing the cancer. Although not the only factor, asbestos exposure is strongly linked to the development of mesothelioma.

When asbestos fibers are inhaled, they can travel into the smallest airways and irritate the lung lining, or pleura. This irritation results in inflammation and damage that can eventually lead to the creation of abnormal cancer cells. There are other areas in the body with a lining similar to the pleura that can also be affected, although much less commonly.

As mesothelioma progresses it may result in fluid accumulation in the pleural space between the lung and the chest wall, causing chest pain and shortness of breath. If left untreated, mesothelioma often spreads to the lymph nodes and progresses rapidly, resulting in death.

Who Is at Risk for Mesothelioma?

The primary risk factor for mesothelioma is asbestos exposure. Asbestos is a heat and fire-resistant mineral fiber that was used in insulation and fire-retardant materials before the 1970s. Though its use has been banned for more than 30 years, occupations such as mining or milling, electricians, plumbers, pipefitters, insulators or even remodelers of older homes still have a high risk of exposure. The longer you are exposed to large amounts of asbestos the more likely you are to develop mesothelioma. That said, most people with asbestos exposure never develop mesothelioma.

If you believe you are exposed to asbestos at work or home, there are steps you can take to limit your exposure and reduce your risk of developing mesothelioma. Ask your employer if you are at risk of inhaling asbestos at your job. Make sure to follow all safety regulations that your employer has laid out, including wearing protective equipment or showering and changing out of work clothes before returning home. If you live in an older home, it is safer to leave asbestos where it is than remove it. Breaking up asbestos fibers will release them into the air, making them easy to inhale. If you believe your home has asbestos, contact a professional to test the air to determine if you are at risk.

Other risk factors include radiation therapy, age and genetics. Radiation pertains particularly to patients who have received high doses of radiation therapy to the chest, such as lymphoma patients. Although the risk of mesothelioma increases with age, even children who have received radiation therapy can get the disease, so if you have received this kind of treatment it is important to speak with your doctor. About 1% of patients diagnosed with mesothelioma have inherited a genetic mutation from a parent that has put them at increased risk of having the disease.

Reviewed and approved by the American Lung Association Scientific and Medical Editorial Review Panel.

Page last updated: November 17, 2022

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