Distal adenomatous polyps are rare in patients with inflammatory bowel disease

There is an increased risk of colorectal cancer in patients with inflammatory bowel disease (IBD). The aim of this study was to compare the prevalence of left sided adenomas in patients with IBD aged 55-64 years with a local age matched control population.

A review of clinical notes. The prevalence of adenomas in patients with IBD attending for either sigmoidoscopy or colonoscopy was compared with local age matched controls that participated in the national screening trial for colorectal cancer with flexible sigmoidoscopy.

Of 106 patients (61 male, 45 female, mean age of 59 years), 80 suffered from ulcerative colitis, 20 from Crohn's disease, and six from indeterminate colitis. All patients had undergone at least one flexible sigmoidoscopy and 75 had a colonoscopy. Distal adenomas were found in three patients with ulcerative colitis compared with 67 of 749 controls (2.8% v 8.9%, chi(2) = 4.6, p = 0.03).

The results suggest that distal adenomatous polyps are rare in patients aged 55-64 years with IBD compared with a control population. This supports the hypothesis that lesions other than polyps are important for the development of colorectal cancer in patients with IBD.