A pilot study to assess the safety and efficacy of the Third Eye retrograde auxiliary imaging system during colonoscopy

Background and study aims: Routine colorectal cancer screening, utilizing optical colonoscopy, has been shown to reduce the incidence and mortality rate of colorectal cancer. Despite its prevalence as the “gold standard” for neoplasia detection, the quality of colonoscopy screening is hindered by missed, undiagnosed lesions that may go undetected when located on the proximal aspect of haustral folds, rectal valves, the ileocecal valve, and/or flexures. The aim of this phase I feasibility trial is to assess the safety and efficacy of a new retrograde auxiliary imaging device, Third Eye™ Retroscope (Avantis Medical Systems, Inc., Sunnyvale, California, USA), used with optical colonoscopy to improve diagnostic yield.

Patients and methods: A total of 29 consecutive patients were enrolled in this phase I single-institution prospective series. Primary efficacy endpoint was identification of polyps in the retrograde image that were not identified in the antegrade image during colonoscope withdrawal.

Results: Of the 29 patients enrolled, 24 patients were treated and 34 out of a total of 38 polyps (classified as either adenoma or hyperplasia) were identified in the antegrade image. An additional four polyps, three hyperplastic and one adenoma, were identified in the retrograde image, and were detected on the proximal aspect of haustral folds during the colonoscope withdrawal, resulting in an 11.8 % increase in diagnostic yield. No adverse events were encountered during the study.

Conclusion: A retrograde auxiliary imaging device used in conjunction with a standard optical colonoscope proved to be safe, technically feasible, and clinically promising. A phase II multi-institutional study is currently underway to further evaluate this device.

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