Cholecystectomy as a risk factor for colorectal cancer: a meta-analysis.
BACKGROUND
It has been suggested that there is an increased risk of colorectal cancer after cholecystectomy due to increased levels of secondary bile acids. Some studies suggest the risk is higher for women and for the development of right-sided tumours.


METHODS
A review of the literature yielded 95 relevant studies, of which 35 were suitable for a meta-analysis involving age- and sex-matched controls.


RESULTS
The pooled odds ratio for a positive association between cholecystectomy and colorectal cancer was 1.11 (95% confidence interval (CI), 1.02 to 1.21). For women the odds ratio was 1.14 (95 % CI, 10.01 to 1.28) and for right-sided cancer 1.86 (95% CI, 1.31 to 2.65).


CONCLUSIONS
It is possible that this small observed association may be due to a publication bias for positive results or bias within the included studies. If it is indeed a real effect, the risk to an individual is very small.
Reid
F D
FD
Dept. of Public Health and Epidemiology, King's College School of Medicine and Dentistry, London, UK.
Mercer
P M
PM
harrison
M
M
Bates
T
T
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001647:Bile Acids and Salts / Q000502:physiology; D002763:Cholecystectomy; D015179:Colorectal Neoplasms / Q000209:etiology* / Q000503:physiopathology; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011183:Postoperative Complications / Q000209:etiology* / Q000503:physiopathology; D012307:Risk Factors; D012737:Sex Factors
D001647:Bile Acids and Salts