The co-localization of carcinomas and adenomas favors a regional field defect in the colon: an observational study.

Abstract

Finding common genetic alterations in colorectal cancers (CRCs) and peri-tumoral mucosa first led to the notion of colonic field defects. The hypothesis of a genetically determined mosaicism would explain these defects and would make the co-localization of tumors likely. Our purpose was to indirectly test this hypothesis by searching for a possible correlation between the location of colorectal cancers and adenomas This is a retrospective observational study. Patients operated for colorectal cancers at an oncological hospital, who had a full colonoscopy performed in the two peri-operative years, were surveyed. Sex, age, familial risk of cancer, tumor and adenoma locations, and the presence of adenomas larger than 1 cm, with villous component or high-grade dysplasia were recorded. T test, chi-square, exact, logistic regression (SPSS18®). This study included 224 patients (57 % male, mean age 67.6 years), 45 % of which had synchronous adenomas. There was a significant correlation between cancer location and location of all adenomas (p = 0.01) and of adenomas larger than 1 cm (p = 0.01). Adenomas of the right colon were more frequent in patients with right colon cancer (p = 0.008), and the same was true on the left colon (p = 0.002). The strong correlation between the locations of CRC and synchronous adenomas, namely risk adenomas, may point to a common early defect. It does also suggest that hemicolectomy may always be the surgery of choice for colon cancer.