Causes and Risk Factors of Mesothelioma

The Roles of Asbestos, Radiation, Genetics, and Smoking

In This Article

Mesothelioma is a deadly cancer that may develop in those exposed to certain triggers, such as asbestos. Someone who has faced such an exposure, such as by working in the construction or remodeling of older buildings or even ships, may have particular concerns about the risks. Discover the roles of asbestos, erionite, radiation, genetics, and potential lifestyle factors like smoking.

Common Causes

The most common cause of mesothelioma is asbestos exposure (either via inhalation or ingestion). Development of mesothelioma usually occurs many years after exposure, often decades, and tracing it back may prove difficult.

Other more rare factors that may contribute to its development include exposure to erionite (a non-asbestos mineral fiber), radiation, or possibly simian virus SV-40. Finally, an inherited genetic susceptibility to negatively reacting to certain mineral fibers may also predispose a person to developing mesothelioma.

Asbestos

Asbestos is a group of minerals that exist in natural mineral deposits. Asbestos, referring to this collective generally, is carcinogenic. This means that it is known to cause cancer. There are many different potential forms with varying associated degrees of danger, and the minerals are often intermixed with each other. Crocidolite (blue asbestos) and amosite (brown asbestos) are thought to be some of the most carcinogenic forms, while chrysotile (white asbestos) is thought to be less carcinogenic but extremely common.

Once present in the mesothelial tissue around the lungs and abdomen, often through inhalation exposure, asbestos causes inflammation. This may ultimately lead to lung disease. Asbestos exposure can also cause minor to moderate respiratory problems like scarring of the lungs (a condition known as pulmonary fibrosis). Chronic inflammation caused by asbestos can also contribute to genetic damage to surrounding cells that may ultimately go on to become mesothelioma. As detailed later, exposure, whether low or high in amount, does not necessarily correlate to symptoms. Some people are exposed and never develop mesothelioma. Many cofactors appear to affect a person’s biological response to asbestos and whether they may go on to develop cancer.

Well into modern history, asbestos was mined and commonly used in building materials, like cement, insulation, and piping. It was frequently used for fireproofing purposes. As a result, it was often present in ship-building, especially in the shipyards during and after World War II. Until the late 20th century, commercial asbestos mining was associated with a high risk of chronic exposure to asbestos. Among those workers who did commercial mining that specifically involved mining of asbestos, it is likely that they would have been exposed to airborne mineral fibers.

Usage in American industry has generally declined since the 1980s, after the dangers associated with it became more evident, but exposure to asbestos in older buildings is still a very real concern. When the asbestos-containing materials are damaged, such as when remodeling occurs, the mineral fibers may enter the air. They can subsequently be inhaled or ingested, leading to the potential risk of developing health problems, sometimes many years later. 

The Occupational Safety and Health Administration (OSHA) restricts exposure to asbestos to minimize the potential risks to workers. Research suggests there may be no safe level of asbestos, so minimizing all exposure and using safety precautions are considered a best practice. Ideally, asbestos materials should be isolated and disposed of properly.

When renovating an older home, or working in an environment where asbestos exposure is possible, ensure safety by requesting information about occupational hazards (required by OSHA), using high-quality respiratory protection, and following safety guidelines when interacting with older materials. Consider these resources:

For those concerned about asbestos exposure in their homes, or who are considering a home remodeling project that might subject them to risky particulate, the Consumer Safety Commission provides information on where it is commonly found, what should be done about the presence of asbestos in your home, and how to manage asbestos problems and mitigate potential risks.

The other potential causes of mesothelioma are much more rare. It is estimated that mesothelioma not known to have been caused by asbestos only occurs in 1 in 1,000,000 people each year.

Erionite

Erionite is a more carcinogenic mineral than asbestos but is also far less common. Mines that operated among zeolite or erionite deposits were mainly in an area of the United States called the Intermountain West which includes Arizona, Oregon, Nevada, Utah, and Texas. Some places within these states may have erionite present in the ambient environment due to natural disturbances of the materials. 

Similar to industrial asbestos, the health risk of erionite is likely exacerbated by the physical disturbance of any erionite that may be present. This allows small particles of the mineral to enter the air and be breathed into the lungs. This can happen during road work or construction where erionite is present in (or on) the soil, or in deposits that are disturbed by digging.

Similarly, large-scale land development that disrupts asbestos and erionite deposits are likely responsible for increasing the amount of mineral fibers in ambient air. There are no regulatory standards for erionite, but it is likely useful to follow protocols used for airborne asbestos to avoid exposure to erionite and its potential health risks.

Though erionite is particularly carcinogenic, its natural rarity and minimal use in industry also make it a very rare cause of mesothelioma in the U.S. However, people who live in the Intermountain West, especially miners, landscapers, and construction workers should be aware of the potential danger of airborne erionite.

Radiation 

A small proportion of people who receive radiation therapy, or other sources of high-dose radiation, may develop mesothelioma in the areas treated. These areas include the mesothelium of the:

  • Lungs (pleura)
  • Abdomen (peritoneum)
  • Heart (pericardium)
  • Testes (tunica vaginalis)

Studies suggest secondary mesothelioma may be found after a period between radiation therapy and secondary mesothelioma that may be 20 or more years on average. Since cancer often occurs later in life, it is possible that mesothelioma that is activated by radiation therapy may never become evident in a person's lifetime. Several long-term studies of mesothelioma suggest that it occurs in less than 0.001% of people who had previously received radiation therapy.

Genetics 

An unclear risk factor in mesothelioma is the role of genetics. As with other cancers, some families appear to be genetically predisposed toward developing the condition, meaning exposure to asbestos-like fibrous minerals leads to a higher rate of development of mesothelioma among these individuals. It is possible that how the body responds to this exposure differs in this susceptible population.

Conversely, some people exposed to large quantities of asbestos never develop mesothelioma, suggesting they do not have the same vulnerability. This may offer some peace of mind to people who may have been inadvertently exposed years ago, before the risks associated with asbestos were fully understood. In fact, only about 5% of people exposed to asbestos ultimately go on to develop mesothelioma.

The genetic basis for the potential risk of developing mesothelioma is still being explored, but some current target gene mutations that appear to increase the risk of mesothelioma include tumor suppressor genes, including:

  • BAP1
  • CDKN2A
  • NF2

These genes, when mutated, may not properly prevent development of mesothelioma and other cancers. Therefore, when the trigger is present, the tissues may be more likely to abnormally develop into cancer.

When present in normal body cells, and not just cancer cells, these mutations may be inheritable. For screening and family health information, genetic testing is available.

Lifestyle Risk Factors

It is not clear that additional lifestyle risk factors, such as smoking, have any impact on susceptibility to mesothelioma. Nevertheless, due to the high rates of developing lung cancer and emphysema, smoking cessation is highly advisable.

It is possible that some non-asbestos carcinogenic chemicals may be responsible, or at least a cofactor, for the development of mesothelioma in rare instances. Further research is necessary to better understand these potential risks.

A Word From Verywell

Mesothelioma can be a scary condition to consider, especially if you have experienced prior exposure to asbestos, erionite, or radiation. Don't allow fear to prevent you from seeking the help that you need to better understand your potential risk. Talk with your doctor about any potential exposure or family history of mesothelioma and further discuss concerns about heritable susceptibility to mesothelioma. Testing may provide some reassurance, and surveillance for the development of the cancer may allow for earlier treatment. Ultimately, educating yourself and preventing exposure may be the best course of action, but the long-term risk may be mitigated by ensuring monitoring for the development of any concerning symptoms.

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Article Sources

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