CT-Colonography vs. Colonoscopy for Detection of High-Risk Sessile Serrated Polyps

• Published in: The American journal of gastroenterology Vol. 111; no. 4; pp. 516 - 522
• Main Authors: IJspeert, J E G, Tutein Nolthenius, C J, Kuipers, E J, van Leerdam, M E, Nio, C Y, Thomeer, M G J, Biermann, K, van de Vijver, M J, Dekker, E, Stoker, J
• Format: Journal Article
• Language: English
• Published: United States Wolters Kluwer Health Medical Research, Lippincott Williams & Wilkins 01.04.2016
• Subjects: Aged; Colonic Polyps - diagnosis; Colonography, Computed Tomographic; Colonoscopy; Female; Gastroenterology; Humans; Male; Mass Screening - methods; Middle Aged; Precancerous Conditions - diagnosis; Risk Factors
• ISSN: 0002-9270; 1572-0241
• DOI: 10.1038/ajg.2016.58

Sessile serrated polyps (SSPs) are suggested to be the precursors of 15-30% of all colorectal cancers (CRCs). Therefore, CRC screening modalities should also be designed to detect high-risk SSPs. We compared computed tomography colonography (CTC) with colonoscopy-based screening for the detection of high-risk SSPs in average-risk individuals. Data from a randomized controlled trial that compared CTC with colonoscopy for population screening were used for the analysis. Individuals diagnosed at CTC with a lesion ≥10 mm in size were referred for colonoscopy. Individuals with only 6-9 mm lesions were offered surveillance CTC. This surveillance CTC was followed by a colonoscopy when a lesion ≥6 mm was detected. Yield of both was accumulated to mimic current American College of Radiology CTC referral strategy (referral of individuals with any lesion ≥6 mm). Per participant detection of ≥1 high-risk (dysplastic and/or ≥10 mm) SSP was compared with colonoscopy using multiple logistic regression analysis. In total, 8,844 individuals were invited to participate (in 2:1 allocation), of which 1,276 colonoscopy and 982 CTC invitees participated in the study. In the colonoscopy arm, 4.3% of individuals were diagnosed with ≥1 high-risk SSP, compared with 0.8% in the CTC arm (odds ratio (OR) 5.5; 95% confidence interval (CI) 2.6-11.6; P<0.001). In total, 3.1% of individuals in the colonoscopy arm were diagnosed with high-risk SSPs as most advanced lesion, compared with 0.4% in the CTC arm (OR 7.7; 95% CI 2.7-21.6; P<0.001). The current CTC strategy showed a marked lower detection for especially flat high-risk SSPs (17 vs. 0), high-risk SSP located in the proximal colon (32 vs. 1), and SSPs with dysplasia (30 vs. 1). In a randomized controlled setting, the detection rate of high-risk SSPs was significantly higher with colonoscopy than CTC. These results might have implications for CTC as a CRC modality for opportunistic screening in average-risk adults.