Risks for mesothelioma

Some things can affect your risk, or chance, of developing cancer. Certain behaviours, substances or conditions can increase or decrease the risk. Most cancers are the result of many risks. But sometimes cancer develops in people who don't have any risks.

Asbestos is the main risk for mesothelioma. This type of cancer affects men much more often than women. This is probably because men are more likely to be exposed to asbestos at work.

The following can increase your risk for mesothelioma. Some of these risks can't be changed. But in other cases, there are things you can do to lower your risk.

Asbestos is the name of a group of minerals that occur naturally. There are several different types of asbestos, including actinolite, amosite, anthophyllite, crocidolite, tremolite and chrysotile.

All forms of asbestos are known to cause cancer, and the link between asbestos and mesothelioma has been well known for many years. Asbestos can be separated into long, thin fibres that are very fine. If these fibres are breathed in, they can make their way into the smallest airways of the lung and into the mesothelium.

When the fibres get into the part of the mesothelium in the chest (called the pleura), they can eventually cause pleural mesothelioma. If they are coughed up and then swallowed, asbestos fibres can also settle in the part of the mesothelium in the abdomen (called the peritoneum) . This is the most likely cause of peritoneal mesothelioma.

In the past, asbestos was used to make products fire-resistant. It was widely used in building materials and in many different industries. But now you can’t mine asbestos or manufacture, import, sell or use products containing asbestos in Canada.

Most people with mesothelioma have a history of asbestos exposure. Occupational exposure to asbestos is the strongest and most common risk factor for mesothelioma. The risk is related to how much asbestos you were exposed to and how long the exposure lasted. People exposed at an early age, for a long period of time and to greater amounts of asbestos are more likely to develop mesothelioma.

People who may come into contact with asbestos while working include:

• workers in asbestos mines or mills
• construction workers, carpenters and painters
• firefighters
• shipyard workers
• cement plant workers
• insulation workers
• electricians
• plumbing and heating tradespeople
• demolition workers
• automotive industry workers, including brake and clutch repair workers
• people who work in buildings where asbestos was present and was disturbed during renovations

Family members of these workers can be exposed to asbestos from fibres that are brought home on clothing. People who lived near an asbestos mine or mill were also exposed to asbestos or asbestos dust in the air.

Mesothelioma develops 15 to 40 years after someone is exposed to asbestos. As a result, it’s uncommon in people younger than 50, and the incidence of mesothelioma increases with age.

Erionite is another naturally occurring material that belongs to a group of minerals called zeolites, which are chemically related to asbestos. Erionite, like asbestos, also has long, thin fibres.

Erionite is linked to both pleural and peritoneal mesothelioma.

Erionite is common in the soil in parts of Turkey. Materials made with erionite are used in construction in these regions. As a result, there are high rates of mesothelioma in these areas due to exposure to erionite.

Fluoro-edenite fibrous amphibole is a naturally occurring mineral that has long, thin fibres like asbestos. It's found in lava flows on the sides of volcanos, especially on Mount Etna in Italy.

Exposure to this mineral increases the risk for mesothelioma.

People who were given radiation therapy to the chest or abdomen to treat cancer, including lymphoma, breast cancer and lung cancer, have a higher risk for mesothelioma.

Thorium dioxide (Thorotrast) is a radioactive contrast medium that was once used for imaging tests. People who were given thorium dioxide have a higher risk of developing mesothelioma, which can appear years after exposure. Because it was found to increase the risk for some cancers, thorium dioxide is no longer used.

The BAP1 gene is also called the BRCA1 associated protein 1 gene. It’s a type of gene that helps control cell growth and may limit the growth of cancer cells (called a tumour suppressor gene). A rare mutation in the BAP1 gene may increase the risk for mesothelioma and melanoma of the skin and eye. Healthcare professionals may refer to people who have the BAP1 gene mutation as having BAP1 cancer syndrome.

People who are exposed to asbestos and have the BAP1 gene mutation are at an even higher risk of developing mesothelioma.

Significant evidence shows no link between mesothelioma and smoking.

To make the decisions that are right for you, ask your healthcare team about risks. Learn how cancer can be prevented and what you can do to reduce your risk.