Lung cancer is the leading cause of cancer death and the second most diagnosed cancer in both men and women in the United States.1 In 2008, 14% of all cancer diagnoses and 28% of all cancer deaths were due to lung cancer.1 After increasing for decades, lung cancer incidence and mortality among men and women are decreasing, paralleling decreases in cigarette smoking.23
Lung cancer begins in the lungs and may spread to lymph nodes or other organs in the body, such as the brain.4 Cancer from other organs may spread to the lungs. When cancer cells spread from one organ to another, they are called metastases.
Lung cancers usually are grouped into two main types called small cell and non-small cell.4 These types of lung cancer grow differently and are treated differently. Non-small cell lung cancer is more common than small cell lung cancer.
Cigarette smoking is the number one cause of lung cancer.5 Lung cancer also can be caused by using other types of tobacco (such as pipes or cigars), breathing secondhand smoke, being exposed to substances such as asbestos or radon at home or work, and having a family history of lung cancer.5