ABSTRACT
AIM: To determine which patients might benefit most from retrograde viewing during colonoscopy through subset analysis of randomized, controlled trial data. METHODS: The Third Eye® Retroscope® Randomized Clinical Evaluation (TERRACE) was a randomized, controlled, multicenter trial designed to evaluate the efficacy of a retrograde-viewing auxiliary imaging device that is used during colonoscopy to provide a second video image which allows viewing of areas on the proximal aspect of haustral folds and flexures that are difficult to see with the colonoscope's forward view. We performed a post-hoc analysis of the TERRACE data to determine whether certain subsets of the patient population would gain more benefit than others from use of the device. Subjects were patients scheduled for colonoscopy for screening, surveillance or diagnostic workup, and each underwent same-day tandem examinations with standard colonoscopy (SC) and Third Eye colonoscopy (TEC), randomized to SC followed by TEC or vice versa. RESULTS: Indication for colonoscopy was screening in 176/345 subjects (51.0%), surveillance after previous polypectomy in 87 (25.2%) and diagnostic workup in 82 (23.8%). In 4 subjects no indication was specified. Previously reported overall results had shown a net additional adenoma detection rate (ADR) with TEC of 23.2% compared to SC. Relative risk (RR) of missing adenomas with SC vs TEC as the initial procedure was 1.92 (P = 0.029). Post-hoc subset analysis shows additional ADRs for TEC compared to SC were 4.4% for screening, 35.7% for surveillance, 55.4% for diagnostic and 40.7% for surveillance and diagnostic combined. The RR of missing adenomas with SC vs TEC was 1.11 (P = 0.815) for screening, 3.15 (P = 0.014) for surveillance, 8.64 (P = 0.039) for diagnostic and 3.34 (P = 0.003) for surveillance and diagnostic combined. Although a multivariate Poisson regression suggested gender as a possibly significant factor, subset analysis showed that the difference between genders was not statistically significant. Age, bowel prep quality and withdrawal time did not significantly affect the RR of missing adenomas with SC vs TEC. Mean sizes of adenomas detected with TEC and SC were similar at 0.59 cm and 0.56 cm, respectively (P = NS). CONCLUSION: TEC allows detection of significantly more adenomas compared to SC in patients undergoing surveillance or diagnostic workup, but not in screening patients (ClinicalTrials.gov Identifier: NCT01044732).
Subject(s)
Adenoma/diagnosis , Colonic Neoplasms/diagnosis , Colonoscopy/methods , Endoscopes , Medical Oncology/methods , Adenoma/pathology , Adult , Aged , Aged, 80 and over , Colonic Neoplasms/pathology , Early Detection of Cancer , Female , Humans , Male , Middle Aged , Multivariate Analysis , Regression Analysis , Reproducibility of ResultsABSTRACT
BACKGROUND: Although colonoscopy is currently the optimal method for detecting colorectal polyps, some are missed. The Third Eye Retroscope provides an additional retrograde view that may detect polyps behind folds. OBJECTIVE: To determine whether the addition of the Third Eye Retroscope to colonoscopy improves the adenoma detection rate. DESIGN: Prospective, multicenter, randomized, controlled trial. SETTING: Nine European and U.S. centers. PATIENTS: Of 448 enrolled subjects, 395 had data for 2 procedures. INTERVENTIONS: Subjects underwent same-day tandem examinations with standard colonoscopy (SC) and Third Eye colonoscopy (TEC). Subjects were randomized to SC followed by TEC or TEC followed by SC. MAIN OUTCOME MEASUREMENTS: Detection rates for all polyps and adenomas with each method. RESULTS: In the per-protocol population, 173 subjects underwent SC and then TEC, and TEC yielded 78 additional polyps (48.8%), including 49 adenomas (45.8%). In 176 subjects undergoing TEC and then SC, SC yielded 31 additional polyps (19.0%), including 26 adenomas (22.6%). Net additional detection rates with TEC were 29.8% for polyps and 23.2% for adenomas. The relative risk of missing with SC compared with TEC was 2.56 for polyps (P < .001) and 1.92 for adenomas (P = .029). Mean withdrawal times for SC and TEC were 7.58 and 9.52 minutes, respectively (P < .001). The median difference in withdrawal times was 1 minute (P < .001). The mean total procedure times for SC and TEC were 16.97 and 20.87 minutes, respectively (P < .001). LIMITATIONS: Despite randomization and a large cohort, there was disparity in polyp prevalence between the 2 groups of subjects. CONCLUSION: The Third Eye Retroscope increases adenoma detection rate by visualizing areas behind folds. ( CLINICAL TRIAL REGISTRATION NUMBER: NCT01044732.).
