Short (35-cm) versus long (60-cm) flexible sigmoidoscopy: a comparison of findings and tolerance in asymptomatic patients screened for colorectal neoplasia.

The purpose of this study was to compare the utility of the 35-cm versus the 60-cm flexible sigmoidoscope in screening asymptomatic patients for colorectal neoplasia. Two hundred fifty-eight patients 45 years of age or older were examined in a randomized fashion with both the 35-cm and 60-cm instruments. Fifteen percent (39/258) of patients had a total of 50 polypoid lesions 3 mm or greater in diameter (including one carcinoma). Of all polypoid lesions, 76% were detected with the 35-cm instrument compared to 98% with the 60-cm sigmoidoscope. Eighty-four percent of all polyps occurred within the distal 35 cm of colon. The mean time required to complete the examination was significantly less with the 35-cm sigmoidoscope than with the 60-cm sigmoidoscope (2.5 vs. 5.7 min). Moderate to severe discomfort was experienced by 69% of patients with the 60-cm instrument compared to only 29% with the 35-cm sigmoidoscope. Seventy-two percent of patients preferred examination with the shorter instrument compared with 7% for the longer sigmoidoscope, while 21% of patients expressed no preference. The 35-cm flexible sigmoidoscope fulfills many criteria of an effective screening test for colorectal neoplasia including rapidity of examination, safety, good sensitivity, and excellent patient acceptance.