Causes of Lung Cancer

Lung cancer is the leading cause of cancer deaths in the United States in both men and women, leading to more deaths than colon, prostate, ovarian and breast cancers combined. It is also one of the most preventable kinds of cancers.

Lung cancer typically begins in the walls of the lungs’ airways or air sacs, but can spread to other parts of the body. There are more than 20 types of lung cancer. The two main types are non-small-cell lung cancer and small-cell lung cancer.


Early stage lung cancer typically presents no symptoms. Signs and symptoms of lung cancer occur when the disease has advanced to a later stage.

These symptoms of lung cancer can include:

  • Chronic cough
  • Shortness of breath
  • Coughing blood
  • Chest pain
  • Weight loss
  • Hoarseness
  • Recurring respiratory infections
  • Wheezing
  • Bone pain
  • Fatigue
  • Headache


Smoking is the primary cause of lung cancer, with around 90 percent of lung cancers occurring as a result of tobacco use.  The risk of lung cancer increases with the number of cigarettes smoked each day and the number of years as a smoker. Quitting at any time lowers the risk of developing lung cancer.

However, smoking is not the only cause of lung cancer. Other causes of lung cancer include:

  • Second-hand smoke – Even if you do not smoke, exposure to second-hand smoke increases the risk of lung cancer. Studies have shown that nonsmokers who live with a smoker have a 24-percent increased risk for developing lung cancer when compared with other nonsmokers. Each year, there are around 7,300 deaths from lung cancer in the U.S. that are attributed to second-hand smoke.
  • Asbestos and other carcinogens - Exposure to asbestos and other substances known to cause cancer – known as carcinogens – such as arsenic, chromium and nickel can increase your risk of developing lung cancer. The workplace is a common source of exposure to asbestos and other carcinogens. Asbestos fibers can live in the lung tissue for a lifetime following exposure. Asbestos workers who are nonsmokers have a five times greater risk of developing lung cancer than other nonsmokers.
  • Radon gas – Radon gas is a natural gas, produced by the breakdown of uranium in soil, rock and water, and which eventually becomes part of the air you breathe. Unsafe levels of radon can accumulate in buildings through gaps in the foundation, pipes, drains, or other openings, and exposure can increase the risk of developing lung cancer.
  • Family or personal history – Lung cancer is more likely to occur in people with a parent, sibling or child who has had lung cancer. This genetic predisposition can occur in smokers and nonsmokers; however, smokers will have an even greater risk. Survivors of lung cancer are also at a greater risk of developing a second lung cancer.

Contact Us

If you are experiencing these symptoms or are concerned about your risk for lung cancer, speak with your primary care physician or contact the Lifespan Cancer Institute.