EFFECTS OF ALPHA-TOCOPHEROL AND BETA-CAROTENE SUPPLEMENTS ON CANCER INCIDENCE IN THE ALPHA-TOCOPHEROL BETA-CAROTENE CANCER PREVENTION STUDY

The Alpha-Tocopherol Beta-Carotene (ATBC) Cancer Prevention Study was a placebo-controlled, randomized intervention trial testing the hypoth esis that beta-carotene and alpha-tocopherol (vitamin E) supplements p revent lung and other cancers. The study is predicated on a substantia l body of evidence supporting a role in cancer prevention for these mi cronutrients. Based on the 2 x 2 factorial study design, 29 133 eligib le male cigarette smokers aged 50-69 y were randomly assigned to recei ve beta-carotene (20 mg), alpha-tocopherol (50 mg), beta-carotene and alpha-tocopherol, or placebo daily for 5-8 y. Capsule compliance was h igh (median = 99%). beta-Carotene treatment did not result in a decrea se in cancer at any of the major sites but rather in an increase at se veral sites, most notably lung, prostate, and stomach (number of cases 474 compared with 402, 138 compared with 112, and 70 compared with 56 , respectively). The vitamin E group had fewer incident cancers of the prostate and colorectum compared with the group not receiving vitamin E (number of cases 99 compared with 151 and 68 compared with 81, resp ectively), but more cancers of the stomach (70 compared with 56). In c ontrast to these intervention-based findings for beta-carotene and vit amin E supplements, we observed lower lung cancer rates in men with hi gher amounts of both serum and dietary beta-carotene and vitamin E at baseline.