What Causes Cancer?
Smoking is the main cause of both types of cancer and about 90 percent of lung cancer deaths are caused by it. Nonsmokers who breathe in smoke from others’ cigarettes are also at increased risk. Nonsmoking spouses of smokers have a 30 percent greater risk of developing lung cancer than do spouses of nonsmokers.

Doctors are treating more nonsmoking women for lung cancer these days and now believe the reason might be that women are more susceptible to other carcinogens.

Other causes of lung cancer include:

• radon, a radioactive gas found in the earth’s soil, is the second leading cause of lung cancer
• occupational or job exposure to asbestos, uranium and coke (an important fuel in the manufacture in iron smelters, blast furnaces, and foundries)
• possibly diet

The American Lung Association is working toward improving the lives of those diagnosed with lung cancer through our work in education, research support and by providing help with treatment options through the NexCura Profiler™. In addition, our tobacco advocacy agenda helps prevent lung cancer by actively promoting efforts to help smokers quit, prevent people from starting to smoke and protect everyone from secondhand smoke.