Lung cancer is the leading cause of cancer deaths in men and women in the United States.
1 Epidemiologic and laboratory animal model studies2–5 have demonstrated that smoking
and environmental exposure to carcinogens are closely linked to increased lung cancer risk.
Tobacco exposure has been implicated in 90% of lung carcinomas, and smokers have a 20-
fold greater risk of acquiring lung cancer compared with persons who have never smoked. 6
Although approximately one half of all people who had ever smoked are now former …