Colonoscopic surveillance of patients with a family history of colon cancer and a history of normal colonoscopy: is a five-year interval between colonoscopies appropriate?

Background & Aims: Patients with a family history of colon cancer are advised to undergo surveillance colonoscopy 5 years after a normal screening colonoscopy. No prospective study has evaluated the prevalence of adenomas found at surveillance colonoscopy in these patients. The aims of this trial were (1) to determine the percentage of these patients with adenomas; (2) to determine the percentage of these patients with advanced adenomas (i.e., villous adenomas, adenomas > or = 10 mm, adenomas with high grade dysplasia); and (3) to assess risk factors for adenomas in these patients.

Methods: Consecutive patients with a family history of colorectal cancer and a normal screening colonoscopy 5 years earlier were offered a surveillance colonoscopy. Patients also completed a questionnaire about potential risk factors for adenomas. Multiple logistic regression analysis assessed associations between risk factors and adenomas.

Results: One hundred patients completed the trial. The male/female ratio was 54/46, the mean age was 56.2 +/- 8.8 years, and 91% were white. Eight percent (8 of 100) of patients had advanced adenomas at surveillance colonoscopy, and 33% (33 of 100) had adenomas. Among patients with adenomas, 39% (13 of 33) had no adenomas in the left side of the colon (i.e., distal to the splenic flexure). Among patients with advanced adenomas, 25% (2 of 8) had no adenomas in the left side of the colon. Multiple logistic regression analysis showed a significant negative association between adenomas and NSAID use (odds ratio, 0.26 [95% confidence interval, 0.09-0.79]), and male gender had a positive association with adenomas (odds ratio, 2.79 [95% confidence interval, 1.01-7.74]).

Conclusions: These data support a 5-year interval between screening and surveillance colonoscopy for patients with a family history of colorectal cancer and a normal screening colonoscopy.