Risk Factors

We do know that a person with certain risk factors may be more likely than others to develop lung cancer.

Risk factors for lung cancer include:

• Tobacco smoke -Tobacco smoke causes most cases of lung cancer. It's by far the most important risk factor for lung cancer. Harmful substances in smoke damage lung cells. That's why smoking cigarettes, pipes, or cigars can cause lung cancer and why secondhand smoke can cause lung cancer in nonsmokers. The more a person is exposed to smoke, the greater the risk of lung cancer.
• Radon - Radon is a radioactive gas that you cannot see, smell, or taste. It forms in soil and rocks. People who work in mines may be exposed to radon. In some parts of the country, radon is found in houses. Radon damages lung cells, and people exposed to radon are at increased risk of lung cancer. The risk of lung cancer from radon is even higher for smokers.
• Asbestos and other substances - People who have certain jobs (such as those who work in the construction and chemical industries) have an increased risk of lung cancer. Exposure to asbestos, arsenic, chromium, nickel, soot, tar, and other substances can cause lung cancer. The risk is highest for those with years of exposure. The risk of lung cancer from these substances is even higher for smokers.
• Air pollution - Air pollution may slightly increase the risk of lung cancer. The risk from air pollution is higher for smokers.
• Family history of lung cancer - People with a father, mother, brother, or sister who had lung cancer may be at slightly increased risk of the disease, even if they don't smoke.
• Personal history of lung cancer - People who have had lung cancer are at increased risk of developing a second lung tumor.
• Age over 65 - Most people are older than 65 years when diagnosed with lung cancer.

Researchers have studied other possible risk factors. For example, having certain lung diseases (such as tuberculosis or bronchitis) for many years may increase the risk of lung cancer. It's not clear whether having certain lung diseases is a risk factor for lung cancer.

People who think they may be at risk for developing lung cancer should talk to their doctor. The doctor may be able to suggest ways to reduce their risk and can plan an appropriate schedule for checkups. For people who have been treated for lung cancer, it's important to have checkups after treatment. The lung tumor may come back after treatment, or another lung tumor may develop.