THE YIELD OF FLEXIBLE SIGMOIDOSCOPY AND DOUBLE-CONTRAST BARIUM ENEMA IN THE DIAGNOSIS OF NEOPLASMS IN THE LARGE-BOWEL IN PATIENTS WITH A POSITIVE HEMOCCULT TEST

Background and Study Aims: In an ongoing screening study of 68 306 patients for early detection of colorectal canter, those with a positive Hemoccult II test (H2) were examined with a flexible sigmoidoscope (60 cm) (FS) and double-contrast barium enema (DCE). The aim of this study was to compare the results of FS and DCE examinations in the rectum and the sigmoid colon, and to evaluate the benefit of DCEs. Patients and Methods: 1831 FS and DCE examinations were performed on the basis of positive H2 tests (90% acceptance rate for positive Hemoccult tests). The radiologists were unaware of the endoscopic findings. One hundred and thirty-five patients underwent total colonoscopy due to abnormalities found on FS or DCE, or both. All patients were followed-up through various Swedish cancer registers (range: 50-145 months). Results: The sigmoidoscope was fully introduced in 71% of cases, and the mean time for the examination was 5 minutes. The combination of FS and DCE detected 235 adenomas of 1 cm and more, and 81 cancers which were in Dukes stages A (n=29), B (n=22), and C (n=23). Twenty-one cancers (26%) and 24 adenomas (10%) identified on DCE were above the rectosigmoid area. The rate of overlooked adenomas (greater than or equal to 1.0 cm) and cancers was 22 and five for FS in the rectosigmoid area, and 55 and 15, respectively, for DCE. Adenomas found in the rectosigmoid area were only rarely associated with more proximal adenomas of 1 cm and more (1%). Conclusions: This approach - screening by FS and DCE, and selective use of colonoscopy in case of abnormalities leads to the diagnosis of significant colonic tumors (larger adenomas and cancers) in 17.7% of cases; only two of eighty-three cancers (2.4%) were overlooked with this method.