Left-sided Polyps Detected at Screening CT Colonography: Do We Need Complete Optical Colonoscopy for Further Evaluation?

Abstract

Purpose:To estimate the relative yield of therapeutic fl exible sigmoidoscopy compared with complete optical colonoscopy for isolated left-sided polyps ( Ն 6 mm in diameter) identifi ed at screening computed tomographic (CT) colonography. Materials and Methods:This retrospective institutional review board-approved and HIPAA-compliant study included a review of CT colonographic screening results in 6570 consecutive asymptomatic adults (3551 women, 3019 men; mean age, 56.8 years 6 7.3 [standard deviation]). Of 887 (13.5%) patients with cases positive for nondiminutive polyps ( Ն 6 mm), a subset of 171 patients met the inclusion criteria (a) of having left-sided-only lesions of 6 mm or larger identifi ed at CT colonography (rectum-to-splenic fl exure) and (b) of undergoing subsequent evaluation with complete optical colonoscopy. CT colonography-optical colonoscopy concordance and proximal-versus-distal diagnostic yield at optical colonoscopy were assessed. The 95% confi dence intervals (CIs) were calculated for relevant results. Results:From the study group of 171 patients, a total of 234 leftsided lesions of 6 mm or larger were prospectively reported at CT colonography, of which 222 (94.9%; 95% CI: 91.3%, 97.0%) were confi rmed as true-positive fi ndings at optical colonoscopy. With optical colonoscopy, an additional 17 benign left-sided polyps of 6 mm or larger (13 small, four large) were found in 11 patients, resulting in a total left-sided yield of 239 nondiminutive lesions, including 137 small polyps (6-9 mm) and 102 large lesions ( Ն 10 mm), 160 neoplasms, 82 advanced adenomas, and seven cancers. Evaluation of the colon proximal to the splenic fl exure in this cohort yielded eight small and two large benign polyps in nine patients but no proximal cancers or histologically advanced lesions. Conclusion:For patients with left-sided-only polyps detected at CT colonography, the additional yield of complete optical colonoscopy beyond the expected reach of fl exible sigmoidoscopy is very low and may not justify the added costs, potential risks, and procedural time.q RSNA, 2011

CT Colonography for Population Screening: Ready for Prime Time?

“…For cases where only left-sided polyps are detected at CTC screening, polypectomy could be more safely performed with sigmoidoscopy over full colonoscopy – with cost savings as well. 47 …”