Lung cancer epidemiology, risk factors, and prevention.

The greatest risk by far for developing lung cancer is cigarette smoking, but age, radon exposure, environmental pollution, occupational exposures, gender, race, and pre-existing lung disease also are important contributors. However, not all people with these risk factors develop lung cancer, and some without any known risk factor do, indicating the importance of genetic influences. Future advances in understanding and treating lung cancer will be based on genetic analysis. The most effective preventive measure is to never start or to stop cigarette smoking.