DNA aneuploidy as a marker of premalignancy in surveillance of patients with ulcerative colitis

Background: Patients with ulcerative colitis have an increased risk of developing colorectal cancer. Specific and sensitive markers for premalignancy are needed. The present study evaluates the status of DNA aneuploidy (abnormal stemlines) as such a marker. Methods: A prospective surveillance programme was conducted for all patients with ulcerative colitis from a defined area. Regular colonoscopy with mucosal sampling for histological evaluation and how cytometric DNA analysis was performed. Some 147 patients were studied from 1984 to 1997. Results: DNA aneuploidy was found in 20 patients. All but one had total colitis. The time from onset of disease to aneuploidy ranged from 5 to 31 years. Fourteen of the patients developed morphological alterations. In the same interval 127 patients, of whom 75 had total colitis, did not develop aneuploidy. Among patients with morphological alterations and aneuploidy, aneuploidy preceded these alterations in four patients and was present at the same examination in three; in seven patients the morphological alterations preceded the aneuploidy. Aneuploidy was diagnosed before the appearance of a dysplasia-associated lesion or mass in four of five cases. Conclusion: Flow cytometric DNA analysis has definite value as a complement to histological examinations in cancer surveillance of patients with ulcerative colitis. Aneuploidy indicates a high risk for developing severe premalignant changes. However, there is no evidence to support the use of DNA aneuploidy as a sole indication for prophylactic surgery against cancer.