A Retrograde-Viewing Auxiliary Imaging Device (Third Eye (R) Retroscope (R) Improves Adenoma Detection Rates (Adr) During Colonoscopy

Purpose: Colonoscopy is currently the best method for detecting and removing colorectal polyps. However, polyps can be missed, especially behind haustral folds, and tandem studies show adenoma miss rates of 21-24%. The Third Eye® Retroscope® (TER) is used with a standard colonoscope to provide an additional, retrograde view that reveals areas behind folds. We evaluated the effect of the TER on adenoma detection rates (ADR) during colonoscopy. Methods: This prospective, multicenter, randomized, controlled trial was undertaken in 5 U.S. and 4 European centers. In total, 448 eligible subjects were enrolled, of whom 372 completed same-day, tandem exams using a standard colonoscope with and without the TER. Subjects were randomized to standard colonoscopy followed by TER (Group A) or TER followed by standard colonoscopy (Group B). Primary outcome measures were detection rates for all polyps and adenomas during standard colonoscopy vs. colonoscopy with TER. ADR in Group B was a proxy for second-pass effect (i.e., just looking a second time may result in detection of additional lesions), and was subtracted from ADR in Group A to yield the net additional detection rate attributed to TER. The primary analysis considered data for the per-protocol (PP) population. Analysis was also performed for the intention-to-treat (ITT) population (Tables 1 & 2).[1386] Table 1. Additional adenoma detection rates for second procedures[1386] Table 2. Lesions per subject missed during first procedures and detected during second proceduresResults: In 173 subjects with standard colonoscopy first (Group A), 107 adenomas were detected, including 21 advanced adenomas. Second procedures with TER yielded 49 adenomas, an additional ADR of 45.8% (Table 1), with 3 advanced adenomas including 2 that were >10 mm. In 176 subjects with TER first (Group B), 115 adenomas were detected, with 27 advanced adenomas including 3 adenocarcinomas. Second procedures with standard colonoscopy yielded 26 adenomas, an additional ADR of 22.6%, including 1 advanced adenoma (3 mm tubular adenoma with high-grade dysplasia). Net additional detection rates with TER were 29.8% for all polyps and 23.2% for adenomas (Table 1). Relative risk of missing lesions with standard colonoscopy vs. TER was 2.56 for all polyps (P<0.001) and 1.92 for adenomas (P=0.029) (Table 2). Mean withdrawal times for standard colonoscopy and TER were 7.58 and 9.52 minutes, respectively (P<0.001). Median difference in withdrawal times was 1.00 minute (P<0.001). Mean total procedure times for standard colonoscopy and TER were 16.97 and 20.87 minutes, respectively (P<0.001). Median difference in total procedure times was 3.37 minutes (P<0.001). Conclusion: The Third Eye® Retroscope® in combination with a colonoscope significantly increases adenoma detection rates (ADR) by visualizing areas behind folds not seen during standard colonoscopy. (ClinicalTrials.gov Identifier: NCT01044732). Disclosure: Dr Siersema - Scientific Advisory Board member: Avantis Medical Systems. All of the other co-authors report no relevant relationships. This research was supported by an industry grant from Avantis Medical Systems.