A comparison of the 25-cm rigid proctosigmoidoscope with the 65-cm flexible endoscope in the screening of patients for colorectal carcinoma.

A comparison of the rigid with the flexible sigmoidoscope was evaluated in 293 patients as part of a screening project for colorectal cancer at Roswell Park Memorial Institute. Patients with either a positive family history for colorectal cancer, a positive stool guaiac test result, a history of hematochezia, or a change in bowel habits were randomly assigned to either rigid or flexible sigmoidoscopy. The median distance of colon examined with the flexible instrument was significantly greater than with the rigid scope (55 versus 17 cm, respectively). A significantly greater number of malignant and premalignant lesions were found with the flexible instrument than with the rigid scope. It was concluded that the flexible sigmoidoscope is superior to the rigid scope in the process of screening for colorectal lesions.