Patients with ulcerative colitis (UC) are prone to colorectal cancer and dysplastic polyps and also have sporadic adenomas. There is scant information, however, relating the prevalence of sporadic adenomas in UC patients compared with normal subjects. The aim of this study was to assess the prevalence of all dysplastic lesions in UC and compare the prevalence of adenomas to that in the general population.

A single-center retrospective study, in which all patients with diagnosed UC were followed during a ten-year period. The incidence of polyps and colorectal cancers were recorded and compared to that of an age-matched group in the general population who had screening colonoscopy.

A total of 229 UC patients were included compared with 450 age-matched subjects who underwent a single colonoscopy. The average number of colonoscopies per UC patient was 3. The rate of sporadic adenomas among UC patients (9.6%), as well as the rate of all dysplastic polyps (11.2%) in these patients, were significantly lower than the rate of adenomas among the control population (24%; OR 0.33–0.44; P<0.0001). Despite this, the rates of colon cancer were comparable between the groups (2.1% vs. 1.5%, P=0.55).

In spite of the observed lower rate of dysplastic polyps in UC patients, this should not preclude tight surveillance in this high-risk population.