The role of sigmoidoscopy for asymptomatic patients

ABSTRACT

A total of 329 asymptomatic patients (aged 50 or older) underwent flexible sigmoidoscopy to screen for colonic neoplasia. Of these, 258 underwent a second examination after 1 year and 143 underwent a third examination after another year. Of 60 patients in whom polyps were found on one of the three examinations, 58 underwent colonoscopy and polypectomy; 77 adenomatous polyps were present in 39 of these patients. The incidence of adenomatous polyps was 7.9 % for the first examination, 3.9 % for the second, and 2.1 % for the third. Of patients with an index polyp found by sigmoidoscopy, 57.5 % had synchronous polyps discovered by colonoscopy. Thirty-six of 77 polyps in 24 patients showed dysplasia; 9 were <0.5 cm, 14 were 0.5 cm to 0.9 cm, and 13 were 1 cm or larger. Forty-four surveillance colonoscopies (done after initial colonoscopy and polypectomy) have been performed in 28 patients. Eighteen examinations resulted in finding 3 0 adenomatous polyps, of which 10 showed dysplasia. This study 1) is the first report of flexible sigmoidoscopy data to support the American Cancer Society recommendation of two serial screening sigmoidoscopies a year apart, 2) reinforces the concept that an index polyp indicates a need for a complete colonoscopy, 3) reinforces the need for ongoing surveillance by colonoscopy after detection of adenomas, and 4) adds to reports of dysplasia in diminutive polyps.