Screening and chemoprevention in lung cancer.

Lung cancer is a major health problem due to its incidence and mortality. The risk factors, the existence of a preclinical phase, and the relationship between stage at diagnosis and survival are known. A number of strategies that aim to diagnose lung cancer in its earliest stages, based principally on imaging studies, are therefore being tested. Several drugs aimed at reducing the probability of developing lung cancer in the at-risk population are also under study. At the present time, the results obtained have not been encouraging and we do not have a clear strategy either for early diagnosis or for the use of chemopreventive agents.