[Mass screening for colorectal cancer by occult blood testing under restricted diet]

We conducted a mass screening survey for colorectal cancer by the combination of fecal occult blood tests under a restricted diet and a medical questionnaire in 7,392 healthy volunteers. Further diagnostic work-up was needed in 1,934 (26.2%) individuals. Of these, 1,409 (72.9%) showed occult blood in at least one slide, 245 (12.7%) had symptoms and 306 (15.8%) had a positive family history. Proctosigmoidoscopy, barium enema and flexible colonoscopy were performed in 1,251, 779 and 95 persons, respectively. Colorectal cancers were detected in 10 individuals (0.14%); 5 of these were in the early stage.