Research confirms that asbestos exposure is the primary cause of mesothelioma. Between 70% and 80% of people diagnosed with mesothelioma have been exposed to asbestos, according to the American Society of Clinical Oncology.
Occupational asbestos exposure accounts for the majority of mesothelioma cases. Asbestos was a sought-after commodity in construction and industry throughout much of the 20th century because of its ability to fireproof and insulate a number of products.
The U.S. military used asbestos extensively on Navy ships. Veterans are at high-risk of having been exposed to asbestos.
The mineral was added to floors, walls, ceilings and roofs of homes, schools, churches and other buildings.
Anyone who worked with asbestos or asbestos-containing products have a higher risk of developing mesothelioma compared to the general public. However, nonoccupational asbestos exposure can also lead to a mesothelioma diagnosis.
Examples of nonoccupational risk factors include secondhand asbestos exposure, living in a residential area with naturally occurring asbestos and exposure to the toxic mineral during home renovations.
How Does Asbestos Cause Mesothelioma?
When raw asbestos or asbestos products are disturbed, microscopic fibers are released into the air. Inhaling or swallowing these fibers can lead to cellular damage.
Our bodies have a hard time removing asbestos fibers. These fibers often become trapped in the thin membranes surrounding the lungs or abdomen.
If asbestos fibers cause enough damage to cells’ DNA, it can result in uncontrolled cell growth and the formation of tumors.
The latency period for mesothelioma is 30 to 50 years. This means it typically takes decades from a person’s first exposure to asbestos to a mesothelioma diagnosis.
Here’s how asbestos can cause pleural mesothelioma, which accounts for 75% of all cases:
- A person inhales microscopic asbestos fibers into their lungs. Heavy exposure over a long period of time increases a person’s risk of developing pleural mesothelioma.
- The fibers travel from the lungs to the pleural lining of the chest wall, where the fibers become trapped and accumulate with repeated exposure.
- After many years, the fibers inflame and irritate mesothelial cells, causing cellular damage, irreversible scarring and cancer.
- The asbestos fibers damage the DNA of cells that make up the pleura, causing uncontrolled cell growth.
- The out-of-control growth of abnormal cells form tumors on the pleural lining.
- As tumors form and grow, they restrict lung function, leading to common mesothelioma symptoms such as shortness of breath and chest pain.
- A mesothelioma diagnosis is usually made when the cancer is in the later stages after symptoms begin and tumor growth is significant.
What Are the Risk Factors of Mesothelioma?
Mesothelioma risk factors are anything that increases the chance of developing the rare cancer.
The primary risk factor for mesothelioma is exposure to asbestos. Common types of asbestos exposure include:
- Occupational Exposure: People who worked in shipyards, factories, power and chemical plants, construction sites or Navy ships until the early 1980s were likely exposed to asbestos. Present-day workers at risk include construction tradesmen, firefighters and mechanics.
- Secondhand Exposure: Many workers unknowingly exposed their spouses and children to asbestos by bringing home toxic dust on their work clothes.
- Environmental Exposure: Asbestos is a naturally occurring mineral. People who live near large deposits in hilly or mountainous regions of the U.S. are at risk. Residents of former asbestos mining towns such as Libby, Montana, are also at high risk for exposure.
- Other Exposures: Disturbing asbestos products during a home renovation can expose anyone in the area if proper safety measures are not met. Asbestos-containing construction materials are prevalent in homes built before 1980.
Additional Mesothelioma Risk Factors
Asbestos exposure is the only defined cause of mesothelioma. The link between asbestos and mesothelioma is so strong that it makes it difficult for researchers to identify other risk factors.
However, research points to several other factors that could increase your risk of developing mesothelioma.
- Exposure to other fibrous minerals such as erionite, zeolite and richterite have been linked to some pleural mesothelioma cases.
- Radiation treatments for other cancers such as lymphoma may increase mesothelioma risk.
- Genetic factors play a role. Research shows mutations of a gene called BAP1 increases the risk of mesothelioma. Scientists are currently studying why some asbestos-exposed people develop the cancer, but most do not.
Researchers have investigated the causal relationship between simian virus 40 (SV40) and malignant pleural mesothelioma since 1994. A polio vaccine was contaminated with SV40 between 1955 and 1963.