Chemoprevention of colon cancer: meta-analysis & systematic review of preclinical studies in rats & mice
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Meta-Analysis of Chemoprevention Studies with Aspirin
in Carcinogen-Initiated Rats and in Min Mice.

Figures: Rat Meta-Analysis <:3 )~~ Min Mice Meta-Analysis

Aspirin Chemoprevention Colon Tumor Incidence in Rats Funnel plot Aspirin Chemoprevention Colon Tumor Incidence in Rats - - <:3 )~~ Aspirin Chemoprevention Intestinal Polyps in Min mice Aspirin Chemoprevention Funnel Plot Min mice

An Explanation of Data Presented Above

Aspirin effect in carcinogen-injected rats. The meta-analysis of eight publications including 811 rats showed that aspirin reduces colon tumour incidence in rats: RR= 0.84 (p=0.006) [Table], with similar RR with Random model analysis (0.86, p=0.007) [Figure]. Analysis of subsets where aspirin was given only before or after the initiation is compatible with the hypothesis that the protection is higher when aspirin treatment is given during initiation.
Aspirin effect in mutated mice. Seven articles including 232 mice with an Apc mutation provide data on aspirin. Number of intestinal adenomas in treated mice was 94% of number in controls (p= 0.59) [Table]. Effect Size analysed by Random Model was -0.29 (p=0.03) [Figure]. This small reduction of small intestinal polyps was thus significant or not, according to model. Furthermore, aspirin treatment did not reduce the number of colonic polyps [Table]. According to Perkins et al. aspirin prevents the early phase of carcinogenesis, and would be active only before birth and until weaning. Data subsets were analysed to test this hypothesis. Mean number of polyps in the two early-treated groups of mice were 74 and 80% of controls , vs. 102% in mice only treated after weaning [Table]. This is compatible with the hypothesis or early protection.
Extracted from the article: "Corpet D.E. & Pierre F., 2005, European Journal of Cancer, How good are Rodent Models of Carcinogenesis in Predicting Efficacy in Humans? Systematic Review and Meta-Analysis of Colon Tumour Chemoprevention in Rats, Mice and Men. in the press." Fetch the [preprint] (.pdf)

Abbreviations /Data Tables

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DE Corpet & F Pierre, 2005, European J. Cancer
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