Rectal biopsy and precancer in ulcerative colitis.

Forty-seven patients with ulcerative colitis subjected to elective proctocolectomy were investigated with regard to the occurrence of precancerous changes in the rectal biopsy and the operation specimen. In the rectal biopsy from seven patients precancerous lesions were found and in the operation specimens from these patients precancer was also found in other parts of the colon. In five of these patients the precancer was associated with carcinoma and in four of the patients the tumour had not been detected before operation. It is concluded that rectal biopsy is of great value in patients with ulcerative colitis for detection of early cancer and patients at risk of developing a colitis carcinoma.