CHEMOPREVENTION OF AERODIGESTIVE CANCER

Effective chemoprevention of aerodigestive tumors could have far-reach ing effects. Aerodigestive cancer accounts for one-third of all cancer deaths in the United States and is the most common cancer in some are as of the world. Prognosis is poor, and a reduced quality of life rema ins in those who do survive. To date, there have been no effective che mopreventive agents, but many new compounds hold promise. The concepts of field carcinogenesis and multi step carcinogenesis underpin the de velopment of chemopreventive agents for aerodigestive tract tumors. Im portant risk factors are tobacco use, alcohol consumption, dietary hab its, genetic susceptibility, socioeconomic status, and the interaction of these. Two promising areas for surrogate biomarker development are tissue autofluorescence and DNA repair. Numerous chemoprevention tria ls have shown that antioxidant compounds are effective in reversing pr ecursor lesions. Studies of the effects of chemopreventive agents on s econd primary tumors are ongoing. Finally, large-scale trials of the a nti-oxidant beta carotene have been disappointing; they have shown tha t among heavy smokers and possibly heavy alcohol consumers beta carote ne increases risk for lung cancer incidence and mortality. These findi ngs underline the critical need to better understand specific mechanis ms of action at a particular tissue site, and under various conditions , such as heavy smoking. Novel agents are under development: epigallac atchin gallate, or green tea, curcumin, and a new emphasis on folic ac id. Studies to date show that targeting susceptible subgroups, by mean s of genetic or lifestyle factors, and all ethnic groups will facilita te the goals of chemoprevention studies.