Key Facts:

  • Mesothelioma is a rare type of cancer that occurs in the lining of the lungs (pleura) and chest wall and less commonly the lining of the abdomen (peritoneum) or in the tissue around the testicles, called the tunica vaginalis.
  • 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.
  • Men are at greater risk, however, the annual number of deaths related to mesothelioma among women significantly increased, from 489 in 1999 to 614 in 2020 . Women dying from mesothelioma more frequently held an occupation in health care, a social assistance industry, or as a homemaker of a spouse exposed 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 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 shortness of breath. Chest pain can occur if the tumor invades or compresses the nerves within the chest. If left untreated, mesothelioma often spreads to the lymph nodes and progresses rapidly, resulting in death.

Who Is at Risk for Mesothelioma?

Asbestos Exposure

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, ship building, ship crew, navy personnel, 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. Secondary exposure for those living with someone who has heavy asbestos exposure may also result in an increased risk due to the fibers being brought into the home environment on the clothes, skin and hair of the individual .  Homemakers of a spouse that works with asbestos have increased risk due to secondary exposure, for example when washing clothing of the individual exposed to asbestos. That said, most people with asbestos exposure never develop mesothelioma.

Occupational Exposure

Certain occupations result in a higher risk of having asbestos exposure.  The following occupations are considered to have increased risk.

  • Mechanics (aircraft and auto)
  • Boiler workers
  • Construction worker
  • Firefighters
  • HVAC workersShipyard workers
  • Industrial workers
  • Insulators
  • Ship Crew, including Navy personnel
  • Machine Operators
  • Machinists
  • Mine workers
  • Firefighters
  • Oil refinery workers
  • Shipyard workers
  • Teachers
  • Textile mill workers


Other Risk Factors

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 patients treated for lymphoma. 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 share that part of your medical history with your healthcare provider. 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.

Steps to Reduce Asbestos Exposure

If you believe you may be exposed to asbestos at work or home, there are steps you can take to limit your exposure and reduce your risk of developing mesothelioma. 

  • Work Exposure

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. 

  • Exposure in Your 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.

Find out more about How to Protect Against Asbestos

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

Page last updated: August 7, 2023

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