Background: Colonoscopic screening can detect neoplasms in asymptomatic adults, many of which would not be detected by sigmoidoscopy. However, because of cost and resource factors, many adults still undergo flexible sigmoidoscopy for colorectal cancer screening. In asymptomatic adults over age 50 undergoing unsedated flexible sigmoidoscopy screening, use of a colonoscope instead of a sigmoidoscope was studied to determine the feasibility, safety, tolerability, and yield.
Methods: Over an 18-month period, asymptomatic adults referred for colorectal cancer screening by sigmoidoscopy were enrolled. Two experienced nurses attempted to reach the cecum by using a pediatric colonoscope but stopped if significant discomfort was experienced, if the preparation was suboptimal, or if polyps were found.
Results: A total of 672 adults (652 men, 20 women) underwent screening. The colonoscope was advanced beyond the level attainable with a sigmoidoscope (70-cm mark) in 240 cases. The cecum was reached in 110 (16.4%) of these patients, with a mean pain intensity for patients of 2.6 (scale 1-10) and a mean time for completion of the procedure of 17 minutes. Colonoscopy to the cecum was not feasible because of patient discomfort in 280 patients (41.7%), poor preparation in 179 (26.7%), left-sided polyps or cancer in 69, and/or severe diverticulosis and tortuosity in 34 cases. Twenty patients had polyps proximal to the 70-cm mark (65% adenomas, no cancer). There was no complication.
Conclusions: The use of a colonoscope instead of a sigmoidoscope by nurses performing unsedated screening sigmoidoscopy is feasible, safe, and well-tolerated, and may improve the yield for screening by at least 16.4% in patients who would otherwise have had only the left colon examined.