A risk factor is any factor that is associated with increasing someone’s chances of developing a certain condition, such as cancer. Some risk factors are modifiable, such as lifestyle or environmental risk factors, and others cannot be modified, such as inherited factors and whether someone in the family has had cancer.

Having one or more risk factor does not mean that you will develop cancer. Many people have at least one risk factor but will never develop cancer, while others with cancer may have had no known risk factors. Even if a person with cancer has a risk factor, it is usually hard to know how much that risk factor contributed to the development of their disease.

Factors that are associated with a higher risk of developing lung cancer include:

Lifestyle factors

• current or former tobacco smoking – this is the greatest risk factor for lung cancer, and the risk is greatest for people who began smoking early in life, smoked for longer and smoked more often

Environmental or occupational factors

• exposure to secondhand smoke (passive smoking)
• occupational exposures, such as radon, asbestos, diesel exhaust and silica. Exposure to asbestos also increases the risk of developing mesothelioma, which starts in the lining surrounding the lungs (the pleura)
• exposure to air pollution

Personal factors

• increasing age
• family history of lung cancer
• a history of chronic lung disease, including chronic obstructive pulmonary disease and pulmonary fibrosis
• a personal history of cancer, including lung cancer, head and neck cancer and bladder cancer.

Find out more about:

• Risk factors for lung cancer: an overview of the evidence
• Cancer Australia Position Statement:  Lifestyle risk factors and the primary prevention of cancer