Causes

Lung Cancer

Anyone can be diagnosed with lung cancer. It affects men, women, smokers, ex-smokers and never smokers.  In fact, 1 in 3 women and 1 in 10 men diagnosed with lung cancer have no history of smoking, and occupational exposure is known to contribute to 29% of lung cancer cases in men.

The cause of lung cancer, and other cancers, is not fully understood. However, it is thought that changes in the genes that program cell functions become faulty. This results in abnormal cell growth and/or multiplication. For many types of cancers, including lung cancer, external influences, such as lifestyle, diet, chemicals and environment, may trigger these faulty genes into action.

Tobacco smoking has been scientifically identified as a cause of lung cancer. However, people who have never smoked can also be diagnosed with the disease. The risk of developing lung cancer decreases in people who stop smoking, but they are still at higher risk than people who have never smoked.

Other risk factors have also been identified as having a link to the development of lung cancer.

These include:

Smoking

And exposure to second-hand smoke

Occupational exposure

Such as asbestos, dust and chemicals

Pollution

Such as chemical, radiation and radon exposure

Genetics

A family history of lung cancer increases the risk for the disease in both smokers and never-smokers.

National Lung Cancer Screening Program

Lung Cancer Screening icon

Please visit the National Lung Cancer Screening Program website to learn more about the new screening program coming in July 2025. The NLCSP website provides participants, healthcare providers and other stakeholders with important information about the program, including:

  • Information about why lung screening is important, who is eligible for the program and details about how lung screening will work
  • Details about the implementation of the program and the work underway to ensure an equitable, accessible and culturally safe national lung screening program from July 2025
  • The important role of healthcare providers and support available to ensure the successful delivery of the program
  • The program’s advisory bodies, clinical and jurisdictions, and contacts for the Department.

The website will be regularly updated as design and implementation continues to progress ahead of the launch of the program in July 2025.

Learn more