PROSTATE-CANCER AND SUPPLEMENTATION WITH ALPHA-TOCOPHEROL AND BETA-CAROTENE - INCIDENCE AND MORTALITY IN A CONTROLLED TRIAL

Background: Epidemiologic studies ha,le suggested that vitamin E and b eta-carotene may each influence the development of prostate cancer, In the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a contro lled trial, we studied the effect of alpha-tocopherol (a form of vitam in E) and beta-carotene supplementation, separately or together, on pr ostate cancer in male smokers, Methods: A total of 29133 male smokers aged 50-69 years from southwestern Finland were randomly assigned to r eceive alpha-tocopherol (50 mg), beta-carotene (20 mg), both agents, o r placebo daily for 5-8 Sears (median, 6.1 years), The supplementation effects were estimated by a proportional hazards model, and two-sided P values were calculated, Results: We found 246 new cases of and 62. deaths from prostate cancer during the follow-up period, A 32% decreas e (95% confidence interval [CI] = -47% to -12%) in the incidence of pr ostate cancer was observed among the subjects receiving alpha-tocopher ol (n = 14564) compared with those not receiving it (n = 14569), The r eduction was evident in clinical prostate cancer but not in latent can cer, Mortality from prostate cancer was 41% lower (95% CI = -65% to -1 %) among men receiving alpha-tocopherol. Among subjects receiving beta -carotene (n = 14560), prostate cancer incidence was 23% higher (95% C I = -4%-59%) and mortality was 15% higher (95% CI = -30%-89%) compared with those not receiving it (n = 14 573), Neither agent had any effec t on the time interval between diagnosis and death, Conclusions: Long- term supplementation with alpha-tocopherol substantially reduced prost ate cancer incidence and mortality in male smokers, Other controlled t rials are required to confirm the findings.