THE YIELD OF FLEXIBLE FIBEROPTIC SIGMOIDOSCOPY IN THE DETECTION OF ASYMPTOMATIC COLORECTAL NEOPLASIA

Recent evidence of a reduction in mortality rates from distal colorect al cancers in populations screened by rigid sigmoidoscopy suggests tha t further benefits may be achieved by the use of fiberoptic sigmoidosc opy as the screening modality. However, there is limited evidence as t o the expected yield of neoplasia using the standard 60-cm instrument. The aim of this study was to determine the yield of neoplasia in an a symptomatic population in the at-risk age group undergoing fiberoptic sigmoidoscopy. Recruitment into the screening program was among State Department personnel. In total, 4,216 asymptomatic subjects (50-65 yea rs) were offered flexible sigmoidoscopic screening performed following a simple enema bowel preparation. Those in whom a neoplastic conditio n was identified underwent further investigation (colonoscopy or bariu m enema). Of those offered screening 4,005 (95%) underwent the examina tion. Eleven carcinomas were detected at flexible sigmoidoscopy and tw o carcinomas were detected at further investigation in subjects with r ectosigmoid polyps. The overall detection rate of carcinomas was 3.2 p er 1,000 subjects screened. Histologically proven adenomas were detect ed in 217 subjects, 5.4% of the population screened. In this cohort of individuals flexible sigmoidoscopy appears to have been an acceptable form of screening. The detection rate of neoplasia, particularly colo rectal adenomas, is higher than that reported from studies of fecal oc cult blood screening.