[Risk of colorectal cancer in ulcerative colitis--monitoring strategies and identification of risk patients].

Patients with ulcerative colitis carry an increased colorectal cancer risk. The cumulative cancer risk for patients with pancolitis is 0.5-0.7% per patient year. Dysplasia as a histologic marker of a neoplastic transformation is used to identify patients with an increased cancer risk during colonoscopic surveillance. Because the classification of dysplasia is subject to inter- and intraobserver variation new methods for the detection of risk patients have been investigated. DNA analysis by flow cytometry seems to be of value for the detection of DNA aneuploidy and the identification of patients who are at risk for neoplastic progression. The significance of DNA aneuploidy is being evaluated in prospective studies. Surveillance guidelines depend on duration and anatomical extent of the colitis as well as on the detection of dysplasia.