Original article
Clinical endoscopy
Effect of a retrograde-viewing device on adenoma detection rate during colonoscopy: the TERRACE study

https://doi.org/10.1016/j.gie.2010.09.004Get rights and content

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.)

Section snippets

Background

In a pilot study of the TER in 24 patients, Triadafilopoulos and Li9 found 11.8% additional polyps behind folds that hid them from the standard colonoscope. Waye et al10 conducted a multicenter study involving 249 subjects. The mean additional detection rates with TER compared with the colonoscope alone were 13.2% for all polyps and 11.0% for adenomas.

A multicenter study with 298 subjects by DeMarco et al11 evaluated the effect of experience with the TER on detection rates and found that after

Methods

Fifteen endoscopists at 4 European and 5 U.S. sites performed at least 10 to 15 practice cases by using the TER before starting the trial. Patients undergoing colonoscopy for screening, surveillance after previous polypectomy, or as a diagnostic workup were recruited. Exclusion criteria included a history of colonic resection, inflammatory bowel disease, polyposis syndrome, radiation therapy to the abdomen or pelvis, suspicion of colonic stricture, active diverticulitis, or concurrent

Patients

In total, 448 subjects were enrolled, of whom 53 (11.8%) had no data collected because they were withdrawn from the study because of technical error or malfunction (n = 6), inadequate bowel preparation (n = 28), previously unrecognized conditions in which back-to-back examinations might increase risk (n = 8), inability to reach the cecum (n = 7), data irretrievably lost by study site (n = 3), and consent withdrawn by patient (n = 1). These subjects did not undergo TEC, and for those who

Discussion

Colorectal cancer is the second largest cause of cancer death in the United States and Europe. In the United States, 152,000 new cases of colorectal cancer were diagnosed in 2009, with more than 50,000 deaths.13 In Western Europe, 436,000 cases were diagnosed in 2008 and 212,000 patients died of the disease.14 This malignancy can be prevented if precancerous adenomas are removed before they progress to adenocarcinomas.1, 2, 15, 16, 17, 18

Colonoscopy is currently regarded as the criterion

References (37)

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DISCLOSURE: Research support for this study was provided by Avantis Medical Systems, Sunnyvale, California. All authors disclosed no financial relationships relevant to this publication. P.D. Siersema is a member of the Scientific Advisory Board of Avantis Medical Systems.

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