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.
- [Aspirin / Rats Table] shows the potency of aspirin on the incidence of colonic tumors in rats (full data, can be searched and sorted)
- [Aspirin / Min Mice Table] shows the potency of aspirin on the number of tumors in the intestine of Min mice (full data, can be sorted)
Figures: Rat Meta-Analysis <:3 )~~ Min Mice Meta-Analysis
- - <:3 )~~
- Aspirin / Rats Figure shows the potency of aspirin on the incidence of colonic tumors in rats (funnel plot)
- Meta-Analysis shareware EasyMA (DOS 2001 version) was used to analyse rat data and draw figures
- Aspirin / Min Mice Figure the potency of aspirin on the number of small intestinal tumors in Apc mutated mice (funnel plot)
- Meta-Analysis shareware EasyMA (online 2005 version) was used to analyse mice data and draw figures
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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- Column "p": NS, Non Significant; MS, Marginally Significant; *, significant: p<0.05 (by Fisher's test).
Last line: Meta-analysis global p value, calculated by Chi-square test, without Yates correction for continuity.
- Columns 3 & 4: Number of tumor-bearing rats in control group (col.3); Total number of control rats (col.4). Control rats' data were duplicated in each line with treated rats data, although control rats were summed only once in last line. Duplicated numbers are tagged with a "-" (e.g., 15- )
- Meta-Analysis Methods, Rats:
See bottom of previous page on Meta Analysis
DE Corpet & F Pierre, 2005, European J. Cancer
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