Chemoprevention of aerodigestive cancer

Effective chemoprevention of aerodigestive tumors could have far- reaching effects. Aerodigestive cancer accounts for one-third of all cancer deaths in the United States and is the most common cancer in some areas of the world. Prognosis is poor, and a reduced quality of life remains in those who do survive. To date, there have been no effective chemopreventive agents, but many new compounds hold promise. The concepts of field carcinogenesis and multi step carcinogenesis underpin the development of chemopreventive agents for aerodigestive tract tumors. Important risk factors are tobacco use, alcohol consumption, dietary habits, genetic susceptibility, socioeconomic status, and the interaction of these. Two promising areas for surrogate biomarker development are tissue autofluorescence and DNA repair. Numerous chemoprevention trials have shown that antioxidant compounds are effective in reversing precursor lesions. Studies of the effects of chemopreventive agents on second primary tumors are ongoing. Finally, large-scale trials of the anti-oxidant beta carotene have been disappointing; they have shown that among heavy smokers and possibly heavy alcohol consumers beta carotene increases risk for lung cancer incidence and mortality. These findings underline the critical need to better understand specific mechanisms of action at a particular tissue site, and under various conditions, such as heavy smoking. Novel agents are under development: epigallacatchin gallate, or green tea, curcumin, and a new emphasis on folic acid. Studies to date show that targeting susceptible subgroups, by means of genetic or lifestyle factors, and all ethnic groups will facilitate the goals of chemoprevention studies.