Antioxidants in oral cancer

Abstract

I present evidence in support of a chemopreven- tive role for the so-called antioxidant nutrients, /3-carotene and vitamin E, against oral cavity cancer. This evidence is from lab- oratory studies, animal model systems. epidemiologic surveys, intervention trials involving reversal of premalignant changes, and prevention of malignancies in particularly high-risk subjects. Be- cause agents proposed for disease prevention are meant to be used widely without close medical supervision. almost any toxicity is unacceptable. /3-Carotene and vitamin E fulfill this criterion for a suitable chemopreventive agent. In several epidemiologic studies, low intakes of vitamin E, carotenoids, or both have been associated with a higher cancer risk. Smoking, a major risk factor, results in lower /3-carotene concentrations in plasma and oral mucosal cells. In several laboratory and animal model systems. /3-carotene and other antioxidant nutrients are inhibitors of oral cavity carcinogen- esis. /3-Carotene and vitamin E can produce clinical regression of oral leukoplakia, a premalignant lesion for oral cancer. The design and limitations of such studies in oral leukoplakia are discussed. Cancer incidence reduction trials in high-risk groups have targeted prevention of second malignancies in patients cured of a primary oral cancer. These trials are in progress. The data thus far are supportive of a significant preventive role for these nutrients in oral cancer. Am J C/in Nutr 1995;62(suppl): l4lOS-6S.