A prospective cohort study on the development of colorectal cancer after gastrectomy.

A prospective cohort study was conducted to examine whether an association exists between gastric surgery and the subsequent development of colorectal carcinoma. One thousand nine hundred twenty-seven patients (1316 men and 611 women) who had undergone curative gastrectomy for gastroduodenal diseases in the First Department of Surgery, Tottori University Hospital, during the 18-year period from 1964 to 1981, were followed to determine the incidence of the development of large-bowel carcinoma after gastric surgery. The age-, sex-, and calendar-specific population at risk was calculated by the person-years method. The observed number of colorectal cancers after gastrectomy was 19 (15 men, 4 women) compared with 9.69 expected carcinomas. The difference between the observed and expected numbers was statistically significant. The authors believe that patients with previous gastrectomy are at high risk for colorectal carcinoma.