Comparison of flexible sigmoidoscopy with other diagnostic techniques in the diagnosis of rectocolon neoplasia.

Flexible sigmoidoscopy was compared to rigid sigmoidoscopy in the detection of colorectal neoplasia in a select group of patients. A distance of 30 cm or greater was obtained by flexible sigmoidoscopy in 94% of patients and a distance of 50 cm or greater in 46% of patients. A significant number of cancers and adenomas detected by flexible sigmoidoscopy were not detected by rigid sigmoidoscopy. Flexible sigmoidoscopy was tolerated better than rigid sigmoidoscopy but required twice the time. Flexible sigmoidoscopy could be combined with air-contrast barium enema the same day with the one preparation and did not interfere with the x-ray examination. All cancers and a significant number of adenomas detected subsequently on colonoscopy were detected by the combination of flexible sigmoidoscopy and air-contrast barium enema. Although the combination of flexible sigmoidoscopy and air-contrast barium enema is not adequate for thorough diagnostic evaluation of patients with a positive screening test, it may be of value in other select clinical situations. Flexible sigmoidoscopy has the potential for higher yield and better patient tolerance as compared to rigid sigmoidoscopy. This warrants further evaluation.