Clinical experience with flexible sigmoidoscopy in asymptomatic and symptomatic patients

The purpose of this study was to evaluate the diagnostic yield of flexible sigmoidoscopy when performed as a routine procedure in asymptomatic patients over the age of 40 being referred for a complete physical examination. The preliminary results of this ongoing program are presented together with the diagnostic yield in 408 patients with symptoms and signs suggestive of colorectal disease who were of similar age (56.6 vs. 56.5 years) and sex distribution (79 percent male) to the asymptomatic population, and who underwent flexible sigmoidoscopy as an indicated part of their evaluation. In the 122 asymptomatic patients, the mean distance examined by the procedure was 50.8 cm with the instrument being advanced beyond the optimal rigid sigmoidoscopy distance of 20 cm in 100 percent of patients. Adenomatous and hyperplastic polyps were identified in 16 patients, 13.1 percent, in the asymptomatic group, a similar percentage to the symptomatic population, 15.4 percent. Adenomatous polyps were diagnosed in 7.4 percent of the asymptomatic subjects and 9.1 percent of the symptomatic group. Colonic cancer was diagnosed in 0.8 percent of asymptomatic patients vs. 3.2 percent of the symptomatic group (p < 0.05). Seventy-seven percent of the neoplastic polyps detected in the asymptomatic patients and 60 percent in the symptomatic group were beyond 20 cm from the anus. Diverticulosis was diagnosed in a similar percentage of patients, 13.1 percent in the asymptomatic and 10.0 percent in the symptomatic group. No complications were encountered and the procedure was well tolerated without analgesia. It is concluded that: (1) in an asymptomatic population over the age of 40, flexible sigmoidoscopy, as a routine examination, results in a diagnostic yield not possible with rigid proctosigmoidoscopy and which approaches that observed in a symptomatic population of similar age; (2) for the internist trained in this procedure, flexible sigmoidoscopy has a future role in the detection of colorectal lesions and as an interval screening examination for premalignant lesions and colorectal cancer in asymptomatic and symptomatic patients.