Assessing Guidelines on the Need for Colonoscopy after Initial Flexible Sigmoidoscopy in Young Patients with Outlet-Type Rectal Bleeding.

Abstract

While young age of onset colorectal cancer is increasing in incidence lack of screening leads to symptomatic presentation, often with rectal bleeding. Because most cancers in patients under 50 are left-sided, flexible sigmoidoscopy is a reasonable way of investigating bleeding in these patients. To predict which patients undergoing flexible sigmoidoscopy for outlet rectal bleeding need a full colonoscopy. Findings at colonoscopy were compared with published indications for colonoscopy after flexible sigmoidoscopy. These were: (1) Any number of advanced adenomas defined as a tubular adenoma >9 mm, a tubulovillous or villous adenoma of any size, or any adenoma with high grade dysplasia. (2) Three or more tubular adenomas of any size or histology. (3) Any sessile serrated lesion. (4) Twenty or more hyperplastic polyps. Charity Hospital with volunteer specialists. Under age 57, outlet type rectal bleeding, undergoing flexible sigmoidoscopy at least to the descending colon, followed by colonoscopy with biopsy of all resected lesions. Flexible sigmoidoscopy and colonoscopy with excision of all removable lesions. Findings at colonoscopy. 66 cases who had a colonoscopy between 5 and 811 days after sigmoidoscopy, who also had complete data. Forty-three male and 23 female with mean age of 39.5 years. Analysis of flexible sigmoidoscopy criteria for finding proximal high-risk lesions on colonoscopy showed a sensitivity of 76.9%, a specificity of 67.9%, a positive predictive value of 37%, a negative predictive value of 92.3%, and an accuracy of 69.7%. Large number of exclusions for inadequate colonoscopy or inadequate data causing reduced patient number in the study. Our criteria for follow-up colonoscopy based on the findings at initial flexible sigmoidoscopy in young patients with outlet rectal bleeding are reliable enough to be used in routine clinical practice, provided this is audited.