Constipation, anthranoid laxatives, melanosis coli, and colon cancer: a risk assessment using aberrant crypt foci

The associations between colorectal cancer (CRC) and constipation, anthranoid laxative use, and melanosis coli are controversial. Aberrant crypt foci (ACF) are microscopic lesions of the colonic mucosa suspected of being preneoplastic, and their investigation has been advocated to evaluate the cause-effect relationship between putative risk factors and CRC. To this aim, we investigated the relationship between sigmoid cancer (SC) and constipation, anthranoid laxative use, and melanosis coli using ACF analysis as an additional tool of investigation. Fifty-five surgical patients with SC, 41 surgical patients with diverticular disease (DD), and 96 age- and sex-matched subjects without intestinal disease (controls) were interviewed on their history of constipation and anthranoid laxative use. Melanosis coli and ACF characteristics were investigated on sigmoid mucosa in patients with SC or DD. Constipation and anthranoid laxative use were similar between patients with SC (30.9% and 32.7%, respectively) and those with DD (39% and 26.8%) but higher than among controls (18.8% and 8.3%). Melanosis coli was found in 38.2% of patients with SC and in 39% of those with DD. Mean ACF frequency was higher in patients with SC (0.24/cm(2)) than in those with DD (0.10/cm(2); P < 0.0001), and it did not vary according to constipation, laxative use, or melanosis coli in either group. This study confirms the association of ACF frequency with colon cancer and does not support the hypothesis of a cause-effect relationship of CRC with constipation, anthranoid laxative, use or melanosis coli.