Risks for lung cancer

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. Smoking tobacco is the main risk for lung cancer.

The risk of developing lung cancer increases with age. More than half of all newly diagnosed lung cancer cases occur among people aged 60 years or older. Men develop lung cancer slightly more often than women. We need more research and can’t say at this time what the risk is for transgender, non-binary and gender-diverse people.

Several things could increase your risk for lung cancer. A few of these can’t be changed. But in some cases, there are things you can do to lower your risk.

All forms of smoking tobacco, particularly cigarettes, increase the risk of lung cancer. The more you smoke and the longer you smoke, the greater your risk of developing lung cancer.

Second-hand smoke also increases your risk of lung cancer.

Find out more about how to live smoke-free.

Radon is a colourless, odourless and tasteless gas that comes from the natural breakdown of uranium in rocks and soil. Radon can seep into buildings through dirt floors or cracks in the foundations. It may reach unsafe levels in enclosed, poorly ventilated spaces.

Radon exposure increases the risk for lung cancer. Radon is the leading risk factor for lung cancer in people who don’t smoke and the second leading risk factor for lung cancer in people who smoke.

Being exposed to higher amounts of radon or being exposed for a long time increases the risk of lung cancer. If you smoke, you are at an even higher risk of developing lung cancer if you are exposed to radon.

Find out more about radon.

Asbestos is the name of a group of minerals that occur naturally. 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.

There are several different types of asbestos, and all are known to cause cancer. While asbestos more often causes mesothelioma, it also increases the risk of lung cancer. People who smoke who are exposed to asbestos have a higher risk of lung cancer.

Find out more about asbestos and cancer.

Coming into contact with the following chemicals at work increases the risk of lung cancer:

• arsenic and inorganic arsenic compounds
• beryllium and beryllium compounds
• cadmium and cadmium compounds
• chemicals used in rubber manufacturing, iron and steel founding, and painting
• chloromethyl ethers and bis(chloromethyl) ether
• chromium (VI) compounds
• diesel engine exhaust
• mustard gas
• radioactive ores such as uranium and plutonium
• silica dust and crystalline silica
• some nickel compounds
• some types of polycyclic aromatic hydrocarbons (PAHs)
• bitumen used in roofing
• cobalt-tungsten carbide
• welding fumes

Some industries use many chemicals, so it is difficult to know which ones increase the risk for lung cancer. People who work in the following industries have the highest risk for lung cancer:

• rubber manufacturing
• iron and steel founding
• coal gasification
• coke (fuel) production
• chimney sweeping
• commercial painting
• firefighting
• roofing and paving
• industries that use the Acheson process to create silicon carbide

Find out more about how to be safe at work.

Air pollution is chemicals, particles and other materials in the air in amounts that could damage the environment or harm the health or comfort of people, animals and plants. Being exposed to outdoor air pollution causes lung cancer. The more air pollution you are exposed to, the greater your risk of lung cancer.

Find out more about air pollution.

People who have had lung cancer before have a higher risk of developing the disease again. You may also have a slightly higher risk for lung cancer if you have a first-degree relative (a brother, sister, child or parent) who has had lung cancer. This could be due to a number of factors, such as shared behaviours (like smoking) or living in the same place where there are carcinogens( like radon).

Some lung diseases or conditions can scar the lungs and increase the risk for lung cancer. These conditions include:

• chronic obstructive pulmonary disease (COPD), which is long-term damage to the lungs that is often caused by smoking
• emphysema and chronic bronchitis, which are types of COPD
• tuberculosis (TB), which is a lung infection caused by tuberculosis bacteria
• a lung infection caused by Chlamydophila pneumoniae

People who were treated with radiation therapy to the chest for certain cancers, such as Hodgkin lymphoma or breast cancer, have a higher risk for lung cancer. These people have an even higher risk if they smoke.

People who were exposed to ionizing radiation during atomic bomb explosions or nuclear accidents have a greater risk of developing lung cancer.

Arsenic can get into drinking water from natural sources in the soil or from certain types of industries, such as mining. Drinking water with arsenic increases the risk of lung cancer. The risk is even greater in people who smoke.

Find out more about arsenic.

An HIV infection can weaken the immune system. People with HIV/AIDS have a higher risk of developing many types of cancer, including lung cancer.

People who have an organ transplant take drugs to suppress their immune system so the body doesn’t reject the organ. Having a suppressed immune system increases their risk of developing lung cancer.

Burning coal indoors for cooking and heating is most strongly linked to lung cancer. Burning wood and other fuels, such as dung or grass, or frying foods in oil at high temperatures can also increase the risk for lung cancer.

Systemic lupus erythematosus is a disease that causes inflammation of the skin, joints, blood vessels, nervous system and internal organs such as the heart, lungs and kidneys. People with lupus have a higher risk for lung cancer.

Beta carotene is a type of antioxidant. People who smoke and take high-dose beta carotene supplements have a higher risk of lung cancer.

The following factors have been linked with lung cancer, but there is not enough evidence to show they are known risk factors. More research is needed to clarify the role of these factors for lung cancer.

There is a possible link between the following chemicals and lung cancer:

• bitumen used in paving
• dixoin used in pesticides
• strong chemical acid mists
• cobalt-tungsten carbide
• antimony trioxide
• benzene

Some families have a strong history of lung cancer, which may mean that they have a change (mutation) in a certain gene that may cause lung cancer. Researchers are trying to find out if a specific gene or genes may increase the risk for lung cancer. Studies are also trying to find very small changes in genes (called genetic polymorphisms) that may increase the risk for lung cancer or make people, especially people who don’t smoke, more sensitive to known risks for lung cancer.

Some studies have shown that long-term smoking of cannabis (marijuana) may increase the risk of lung cancer, but other studies have not found a link.

Research suggests that people who are not physically active may have a higher risk for lung cancer, whether they smoke or not.

Some studies report that people who eat a diet high in vegetables and fruit have a lower risk for lung cancer.

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