Precancer and cancer in extensive ulcerative colitis: findings among 401 patients over 22 years.

Patients with extensive ulcerative colitis who do not need early surgery have been offered regular examination with the aim of detecting precancerous change (dysplasia) or early colorectal carcinoma. Outpatient visits with clinical examination, sigmoidoscopy, and biopsy were supplemented by two-yearly colonoscopy after the disease course reached 10 years. During the 22 year period from the beginning of 1966 to the end of 1987, 401 patients entered the programme and together contributed 4048 patient-years of observation. Apart from nine patients who left the country, follow up is complete until 1986 or 1987. Colorectal carcinoma developed in 22 patients and, in a further 12, biopsy evidence of precancer, described as severe/high grade dysplasia, was confirmed in a colectomy specimen. The cumulative probability of developing carcinoma was 3% at 15 years, 5% at 20 years, and 9% at 25 years; corresponding figures for precancer or carcinoma, or both were 4%, 7%, and 13%. Five patients died of colorectal carcinoma, two while under regular observation and three after developing carcinoma four to six years after their last attendance. Among the 17 patients who developed carcinoma while under observation, the Dukes stage was A or B in 12. Patients with extensive colitis whose disability does not warrant early surgery have a clinically important cancer risk after the disease has been present for 10 years. Our results suggest that follow up in the manner described reduces the mortality from this complication. Further work is needed to define the optimum method of surveillance and show if it is cost effective.