[Chemoprevention in head and neck cancer and lung cancer]

Because of their raised prevalence and mortality, association of secondary tumors and inefficiency of therapeutic conventional (surgery, radio- and chemotherapy), head and neck and lung cancers represent true public health problems. The knowledge of the process of carcinogenesis allowed development of approaches of chemoprevention. The vitamin A and its derivatives showed initially a certain efficacy, but an important toxicity and large trials remained negative. For lung cancers, in the event of continuation of the tobacco, beta-carotene and the vitamin A seem even deleterious. Progress in the biology of cancer should allow innovating new approaches of chemoprevention. Today the most effective strategy stays the stop of the tobacco.