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

Background: Although 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 younger than 50 years are left-sided, flexible sigmoidoscopy is a reasonable way of investigating bleeding in these patients.

Objective: To predict which patients undergoing flexible sigmoidoscopy for outlet-type rectal bleeding need a full colonoscopy.