Prostate cancer and supplementation with alpha-tocopherol and beta-carotene: incidence and mortality in a controlled trial.
BACKGROUND
Epidemiologic studies have suggested that vitamin E and beta-carotene may each influence the development of prostate cancer. In the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a controlled trial, we studied the effect of alpha-tocopherol (a form of vitamin E) and beta-carotene supplementation, separately or together, on prostate cancer in male smokers.


METHODS
A total of 29133 male smokers aged 50-69 years from southwestern Finland were randomly assigned to receive alpha-tocopherol (50 mg), beta-carotene (20 mg), both agents, or placebo daily for 5-8 years (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% decrease (95% confidence interval [CI] = -47% to -12%) in the incidence of prostate cancer was observed among the subjects receiving alpha-tocopherol (n = 14564) compared with those not receiving it (n = 14569). The reduction was evident in clinical prostate cancer but not in latent cancer. 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% CI = -4%-59%) and mortality was 15% higher (95% CI = -30%-89%) compared with those not receiving it (n = 14573). Neither agent had any effect on the time interval between diagnosis and death.


CONCLUSIONS
Long-term supplementation with alpha-tocopherol substantially reduced prostate cancer incidence and mortality in male smokers. Other controlled trials are required to confirm the findings.
Heinonen
O P
OP
Department of Public Health, University of Helsinki, Finland.
Albanes
D
D
Virtamo
J
J
Taylor
P R
PR
Huttunen
J K
JK
Hartman
A M
AM
Haapakoski
J
J
Malila
N
N
Rautalahti
M
M
Ripatti
S
S
Mäenpää
H
H
Teerenhovi
L
L
Koss
L
L
Virolainen
M
M
Edwards
B K
BK
D016588:Anticarcinogenic Agents / Q000627:therapeutic use*; D004311:Double-Blind Method; D006801:Humans; D015994:Incidence; D008297:Male; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000517:prevention & control*; D016896:Treatment Outcome; D014810:Vitamin E / Q000627:therapeutic use*; D019207:beta Carotene / Q000627:therapeutic use*
D016588:Anticarcinogenic Agents; D019207:beta Carotene; D014810:Vitamin E