Definition

Lung cancer is the leading cause of cancer deaths in the United States, among both men and women. It claims more lives each year than colon, prostate, lymph and breast cancers combined.
Yet most lung cancer deaths could be prevented. That's because smoking accounts for nearly 90 percent of lung cancer cases. Your risk of lung cancer increases with the length of time and number of cigarettes you smoke. If you quit smoking, even after smoking for many years, you can significantly reduce your chances of developing lung cancer. Protecting yourself from other risk factors for lung cancer, such as exposure to asbestos, radon and secondhand smoke, also decreases your risk.