Lung cancer is one of the most common cancers in the world and is the leading cause of cancer death in men and women in the United States. Over 150,000 people die in the U.S. every year from lung cancer. Most lung cancers are caused by cigarette smoking. The more cigarettes you smoke per day and the earlier you started smoking, the greater your risk of lung cancer. Second-hand smoke has also been shown to increase risk. Government surveys show that as many as 3,000 people each year develop lung cancer from second-hand smoke. High levels of pollution, radiation, and asbestos exposure may also increase risk. Lung cancer begins in cells that line the airways and usually invades adjacent tissues or other organs before symptoms are noticed.
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