A cooperative study on the detection of colorectal cancer and polyps in France.

Systematic investigations testing for the presence of polyps and cancers of the large bowel were conducted in a population of 1,369 inpatients and outpatients, aged 45-70 years, in eight university departments of gastroenterology or abdominal surgery (Toulouse, Dijon, Paris, Marseille, and Strasbourg). Double-contrast barium enema and proctosigmoidoscopy examinations were carried out in all cases, whereas total coloscopy was performed only in the case of detected tumors. A questionnaire including 233 parameters (age, sex, family, and personal history and symptoms) was completed for each patient. A total of 414 lesions were detected in 252 patients, including 245 adenomatous or villous polyps, 8 transformed polyps, and 30 carcinomas; 3 of 4 lesions were located in the rectum or sigmoid. Cancer or adenomatous or villous polyps were found in 13% of the patients. The prevalence of these lesions in the population studied was increased in patients with rectorrhagia (19%) or with a personal history of surgery for colorectal cancer or polyp (23%). In the patients without rectorrhagia or a history of intestinal tumor, the incidence was 9.7%. It was significantly increased in males and patients more than 50 year old. The efficacy of proctosigmoidoscopy and double-contrast barium enema was compared in 909 patients. Sensitivity and specificity were, respectively, 35% and 99% for endoscopy, 96% and 94% for radiology.