Document Detail

Antioxidants in the chemoprevention of colorectal cancer and colorectal adenomas in the general population: a systematic review and meta-analysis.
MedLine Citation:
PMID:  20412095     Owner:  NLM     Status:  In-Data-Review    
Aim  Antioxidants, such as vitamin A, C and E, selenium and β-carotene, have been proposed as possible agents in the chemoprevention of colorectal cancer and have been the subject of recent trials and reviews. This review aimed to assess the present evidence on the effect of antioxidants on the incidence of colorectal neoplasms in the general population. Method  A systematic review of randomized controlled trials was undertaken comparing antioxidants alone or in combination with other agents vs placebo. The following databases were searched for published and unpublished literature: Cochrane Library, MEDLINE, PreMEDLINE, CINAHL, EMBASE, Web of Science, and Biological Abstracts and Research Registers. Studies were quality appraised and extracted. Meta-analysis was performed. Results  Twelve studies were identified as relevant. In the nine comparing antioxidants with no antioxidants (n = 148 922), there was no difference in the incidence of colorectal cancer [relative risk (RR) 1.00, 95% confidence interval (CI) 0.88-1.13]. One study assessed the effect of antioxidants on adenoma formation (n = 15 538) and did not demonstrate a statistically significant effect (RR 1.47, 95% CI 0.97-2.23). Of 14 discrete analyses for different combinations of antioxidants, only one reported a statistically significant increase in relative risk of adenoma formation in participants receiving vitamin E (RR 1.74, 95% CI 1.09-1.79, P = 0.02) or vitamin E plus β-carotene (RR 1.63, 95% CI 1.01-2.63, P = 0.04). Effectiveness did not seem to differ between healthy populations, participants with cardiovascular risk factors or populations exposed to smoking or asbestos. Conclusion  The review demonstrates that antioxidants (vitamin A, C and E, selenium and β-carotene), as single agents, in combination with other antioxidants or in combination with other agents, are not effective in the chemoprevention of colorectal neoplasia in the general population. This questions their involvement in future randomized controlled trials of chemoprevention in colorectal cancer.
D Papaioannou; K L Cooper; C Carroll; D Hind; H Squires; P Tappenden; R F Logan
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Publication Detail:
Type:  Journal Article     Date:  2010-04-19
Journal Detail:
Title:  Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland     Volume:  13     ISSN:  1463-1318     ISO Abbreviation:  Colorectal Dis     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-09-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100883611     Medline TA:  Colorectal Dis     Country:  England    
Other Details:
Languages:  eng     Pagination:  1085-99     Citation Subset:  IM    
Copyright Information:
© 2011 The Authors. Colorectal Disease © 2011 The Association of Coloproctology of Great Britain and Ireland.
Health Economics and Decision Science (HEDS), School of Health and Related Research (ScHARR), University of Sheffield, Sheffield Epidemiology and Public Health, University of Nottingham, Nottingham, UK.
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