From: Doug Skrecky (oberon@vcn.bc.ca)
Date: Fri Jun 04 1999 - 07:30:18 MDT
Citations: 1-2
<1>
Authors
Omenn GS.
Institution
School of Public Health & Community Medicine, University of Washington,
Seattle 98195-7230, USA. gomenn@umich.edu
Title
Chemoprevention of lung cancer: the rise and demise of
beta-carotene. [Review] [124 refs]
Source
Annual Review of Public Health. 19:73-99, 1998.
Abstract
Beta-carotene and retinoids were the most
promising agents against common cancers when the National Cancer Institute
mounted a substantial program of population-based trials in the early 1980s.
Both major lung cancer chemoprevention trials not only showed no benefit, but
had significant increases in lung cancer incidence and in cardiovascular and
total mortality. A new generation of laboratory research has
been stimulated. Rational public health recommendations at this time include:
1. Five-A-Day servings of fruits and vegetables, a doubling of current mean
intake; 2. systematic investigation of the covariates of extremes of fruit
and vegetable intake; 3. discouragement of
beta-carotene supplement use, due to
adverse effects in smokers and no evidence of benefit in non-smokers; 4.
multilevel research to develop and evaluate candidate chemoprevention agents
to prevent lung and other common cancers; and 5. continued priority for
smoking prevention, smoking cessation, and avoidance of known carcinogens in
the environment. [References: 124]
<2>
Authors
Heinonen OP. Albanes D. Virtamo J. Taylor PR. Huttunen JK. Hartman AM.
Haapakoski J. Malila N. Rautalahti M. Ripatti S. Maenpaa H. Teerenhovi
L. Koss L. Virolainen M. Edwards BK.
Institution
Department of Public Health, University of Helsinki, Finland.
Title
Prostate cancer and supplementation with alpha-tocopherol and
beta-carotene: incidence and
mortality in a controlled trial [see comments].
Comments
Comment in: J Natl Cancer Inst 1998 Mar 18;90(6):414-5, Comment in: J Natl
Cancer Inst 1998 Mar 18;90(6):416-7
Source
Journal of the National Cancer Institute. 90(6):440-6, 1998 Mar 18.
Abstract
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.
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