Combined Forward and Retroflexion Withdrawal in the Detection of Polyps and Adenoma During Colonoscopy

Summary

Colonoscopy is the standard of care for the detection of colorectal polyps and adenoma, and colorectal cancer detection. Despite a meticulous evaluation of the colonic mucosa during colonoscopy, a substantial number of colorectal polyps might be missed and colorectal cancer might not be prevented.

Previous studies described a 12-28% of miss-rate for all polyps, a 31% for hyperplastic polyps and 6-27% for adenomas, with a higher miss rate noted for smaller polyps. The lesion missing rate depends on several factors, such as the location on difficult areas to be evaluated with conventional colonoscopes (the proximal side of the ileocecal valve, haustral folds, flexures or rectal valves), a flat shape, an inadequate bowel preparation and inadequate endoscopy technique, a time-limited colonoscope withdrawal.

If the standard 140º angle of view colonoscope is used approximately 13% of the colonic surface is unevaluated. The incorporation of colonoscopes with a 170-degree wide angled could improve adenoma detection rate.

The introduction of high definition (HD) colonoscopes and visual image enhancement technologies, such as narrow band imaging (NBI, Olympus America, Center Valley, PA), I-SCAN™ (Pentax Medical, Montvale, NJ) and Fuji Intelligent Chromo-Endoscopy (FICE™, Fujinon Endoscopy, Wayne, NJ) have improved the lesion characterization; however, several studies have failed to prove an increase in the adenoma detection rates.

The Third Eye Retroscope (Avantis Medical Systems, Sunnyvale, CA) is a disposable retrograde viewing device advanced through the accessory channel of a standard colonoscope. It allows retrograde viewing behind colonic folds and flexures simultaneously with the forward view of the colon. Although it shows an increase in the adenoma detection rate by 11%-25%, it has many disadvantages. First, it requires a separate processor and the device is disposable, increasing the cost of the procedure. Second, it occupies the working channel of the colonoscope, limiting the ability to suction. Third, if a polyp is detected, the viewing device has to be removed in order to perform the polypectomy. Fourth, the optic is not high definition and finally, the endoscopist has to get used to visualizing and processing two simultaneous video streams from the colonoscopy and from the retroscope device.

Conditions

• Colonic Polyp
• Colonic Neoplasms
• Colonic Adenoma

Interventions

DIAGNOSTIC_TEST

Colonoscopy with Retroview scope combing forward and retroflexed withdrawal technique

Colonoscopy using a combined forward and retroflexed evaluation of the colonic mucosa. using the Retroview™ scope. The operator will be blind to the standard colonoscopy findings. The operator will record the polyps and adenoma encountered, describing the size and location.

DIAGNOSTIC_TEST

Colonoscopy with standard colonoscope and forward withdrawal technique

A standard colonoscopy with forwarding viewing withdrawal technique. An HD colonoscope with I-scan technology will be used by one expert endoscopist. Each polyp and adenoma will be recorded, including the size and location.

Sponsors & Collaborators

• Instituto Ecuatoriano de Enfermedades Digestivas

  lead OTHER

Principal Investigators

• Carlos Robles-Medranda, MC · Instituto Ecuatoriano de Enfermedades Digestivas

Study Design

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

45 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2019-01-02

Primary Completion

2020-12-01

Completion

2021-01-01

Countries

• Ecuador

Study Locations