Carcinomas of the colon and rectum that develop in patients with chronic ulcerative colitis (CUC) are believed to differ in several ways from those that are observed in the general population (hereafter known as normals). Generally, they are considered to be more common, to develop more frequently in the proximal colon, to occur in younger patients, and to carry a graver prognosis. In this paper, the evidence supporting these conclusions will be considered. Data will be drawn from a study of the 750 patients with CUC who entered the Massachusetts General Hospital from 1943 to 1962.
At the outset, it is well to outline some of the differences involved in any statistical study of this type. In the first place, the population of patients with CUC cannot be defined exactly because of inaccuracies in diagnosis among hospitalized patients as well as the fact that an indefinite number of patients do