Retroview™ Colonoscope and Lesion Detection Rate

February 25, 2019 updated by: Instituto Ecuatoriano de Enfermedades Digestivas

Retroview™ vs. Conventional Colonoscopy: it is Time to Change?

Colonoscopy is considered the gold standard for colorectal polyp and cancer detection. However, even meticulous colonoscopy substantial numbers of colorectal polyps may be missed and carcinomas may not be prevented. Previous studies have found a 12-28% of miss rate for all polyps, a 31% for hyperplastic polyps and 6-27% for adenomas, with the higher miss rates noted for smaller polyps. The lesions missing rate depends on several factors 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, a poor bowel preparation and inadequate endoscopy technique, particularly rapid colonoscope withdrawal. Using the commonly available 140º angle of view colonoscope, approximately 13% of the colonic surface is unseen. The incorporation of colonoscopes with a 170-degree wide angled could not improve adenoma detection rate. The introduction of high definition (HD) colonoscopes and visual image enhancement technologies as narrow band imaging (NBI, Olympus America, Center Valley, PA), i-SCAN™ (PENTAX of America, Montvale, NJ) and Fuji Intelligent Chromo-Endoscopy (FICE™, Fujinon Endoscopy, Wayne, NJ) have improved the lesion characterization, but several studies proved no increase in adenoma detection rates. The Third Eye Retroscope (Avantis Medical Systems, Sunnyvale, CA) is a disposable retrograde viewing device advanced via the accessory channel of a standard colonoscope. Allows retrograde views behind colonic folds and flexures simultaneously with the forward view of the colon. Although it was shown an increase in adenoma detection rate by 11%-25%, it has many disadvantages. It requires a separate processor and the device is disposable making the cost bigger. Occupies the working channel of the colonoscope which limits the ability to suction. If a polyp is seen the viewing device has to be removed in order to perform the polypectomy. The optic is not high definition and finally, the endoscopist has to get used to visualizing and processing two simultaneous video streams from the colonoscope and from the retroscope device.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The Retroview™ (PENTAX Medical, HOYA Co.) colonoscope has a short turning radius at the colonoscope tip, that allows a retroflexed view of the colon during withdrawal. This may allow for detection of polyps hidden behind flexures, folds and valves, from the cecum to the rectum. It offers many advantages like the ability to provide high definition views of the proximal aspects of colonic folds, flexures and valves with no additional equipment or device costs. The image is high definition and the colonoscope also incorporates i-SCAN technology. The suction/work channel of the colonoscope is available for therapeutic procedures. Polypectomy can be performed with the colonoscope in retroflexion, without losing views of the polyp. The only disadvantages are the higher consumed withdrawal time because the additional retroflexed withdrawal to the standard withdrawal and that a small portion of the colon is obscured by the shaft of the colonoscope in retroflexion that may be the reason why combined standard withdrawal with retroflexed withdrawal has proved to be better than retroflexed withdrawal alone.

The aim of this study is to determinate and compare the polyp / adenoma detection rate and lesion miss rate by performing a colonoscopy using conventional scopes vs PENTAX RetroView™ scope. As a secondary outcome, size of lesions will be measure in order to determinate if there is a difference between both technics.

MATERIALS AND METHODS

Setting: Instituto Ecuatoriano de Enfermedades Digestivas (IECED), Omni Hospital Academic Tertiary Center. We will include patients from December 2016 to July 2017. The study protocol and consent form has been approved by the Institutional Review Board and will be conducted according to the declaration of Helsinki. Patients will sign an informed consent.

Intervention: endoscopic technique The colonoscopy will be performed, in all cases, twice with 2 different scopes. One is a conventional HD colonoscope with I-Scan, tube diameter of 13.2 mm and total length 2023 mm (standard EC 3490LK, PENTAX, Montvale, NJ) and the other is the Retroview™ colonoscope with tube diameter of 11.6 mm and total length 2023 mm (EC-3490TLi, PENTAX, Montvale, NJ). The endoscopy images will be seen on a 27-inch, flat panel, HD LCD monitor (Radiance™ ultra SC-WU27-G1520 model). All of the participants will follow the same colonic preparation with 4 liters of polyethylene glycol (PEG) the day before and the bowel preparation will be evaluated using the Boston Bowel Preparation Scale. Two trained endoscopists on retroflex withdrawal will perform the colonoscopies. Both colonoscopies will be performed in tandem. First one endoscopist will perform the conventional colonoscopy using standard withdrawal technique and then the second endoscopist blinded to the first colonoscopy results, will perform the second colonoscopy with the Retroview scope and combination withdrawal (retroflexed + standard withdrawal). The endoscopist that will perform each colonoscopy will be chosen randomly. The minimum withdrawal time of 6 minutes that is recommended in literature will be respected in both cases. After the examination, the endoscopist will fill a questionnaire detailing each polyp / adenoma found including the size and location. The withdrawal time will be measured in both colonoscopies.

Statistical analysis: Baseline characteristics will be analyzed using Chi-square o Fisher Test for categorical variable and Mann-Whitney Test for continuing variables. If there are more than one polyp in one patients it will be considered individually for statistical purposes. A P value of less than 0.05 will be considered to be statistically significant. All the statistical analysis will be performed using SPSS software suite v.22.

Limitations: The protocol will be performed in only one center and by two endoscopists. There is no control group because the intention is to compare two endoscopy methods in the same setting.

Study Type

Observational

Enrollment (Actual)

100

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Ecuador
    • Guayas
      • Guayaquil, Guayas, Ecuador, 090505
        • Ecuadorian Institute of Digestive Diseases, Omnihospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 80 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients will be recruited from the gastroenterology unit (IECED). All of the participants will have a clear colonoscopy indication. Group A will include patients that have a polyp already seen in a previous colonoscopy and the colonoscopy is indicated for polypectomy. Group B will include the rest of indicated colonoscopies. The distribution in groups A and B is with no intention to compeer the groups but in order to avoid a bias because the patients already have a known lesion.

Description

Inclusion Criteria:

  • Patients that agree to participate in the study.
  • Able to understand and provide written informed consent.
  • Colonoscopy indication for colorectal neoplasia screening or polyp surveillance.
  • Colonoscopy indication for polypectomy.
  • Colonoscopy indication for diagnostic workup including anemia, abdominal pain, constipation, abnormal imaging.

Exclusion Criteria:

  • Age under 18 and over 80 years' old.
  • Pregnancy
  • Patients with heart disease, kidney, liver or severe metabolic disorder, who cannot tolerate sedation.
  • Severe uncontrolled coagulopathy.
  • Patients with difficulty understanding instructions of bowel preparation.
  • Prior history of colon resection.
  • Patients with an ileostomy or a colostomy.
  • Abdomen or pelvis radiation therapy.
  • Known inflammatory bowel disease, polyposis syndrome or acute diverticulitis.
  • Suspected colonic obstruction or history of previous obstruction.
  • Gastrointestinal bleeding.
  • Lack of acceptance by the patient.
  • Bowel preparation will be evaluated using the Boston Bowel Preparation Scale. Patients with < 2 points in at least one of the three segments of the colon (rectum plus left-side colon, transverse colon plus left and right flexure, right-side colon) will be excluded from statistical analysis as well as those who after the beginning of the colonoscopy, had to be aborted because of an inability to reach the cecum by unfavorable anatomy or impassable tumors / stenosis.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Group A Retroview™ colonoscope
Patients that have a polyp already seen in a previous colonoscopy and the colonoscopy is indicated for polypectomy will be submitted to a Retroview™ colonoscope
Device: Retroview™ colonoscope
The colonoscopy will be performed twice, with 2 different scopes, in tandem, by 2 endoscopists trained on retroflex withdrawal. First a conventional HD colonoscope with I-Scan will be used following the standard withdrawal technique and then the second endoscopist blinded to the first colonoscopy results, will perform the second colonoscopy using the Retroview™ scope with a combining withdrawal (retroflexed + standard withdrawal). The endoscopist that will perform each colonoscopy will be chosen randomly. After the examination, the endoscopist will fill a questionnaire detailing each polyp / adenoma found including the size and location.
Group B Retroview™ colonoscope
The rest of colonoscopies indicated will be submitted to a Retroview™ colonoscope
Device: Retroview™ colonoscope
The colonoscopy will be performed twice, with 2 different scopes, in tandem, by 2 endoscopists trained on retroflex withdrawal. First a conventional HD colonoscope with I-Scan will be used following the standard withdrawal technique and then the second endoscopist blinded to the first colonoscopy results, will perform the second colonoscopy using the Retroview™ scope with a combining withdrawal (retroflexed + standard withdrawal). The endoscopist that will perform each colonoscopy will be chosen randomly. After the examination, the endoscopist will fill a questionnaire detailing each polyp / adenoma found including the size and location.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Polyp detection rate with the standard colonoscope and Retroview™ scope.
Time Frame: 8 month
Polyps found with standard colonoscope / total of polys found X 100; polyps found with Retroview™ scope / total of polys found X 100; The total of polyps found will be determinated by the combination of both technics (standard colonoscope and Retroview™ scope)
8 month
Adenoma detection rate with the standard colonoscope and Retroview™ scope.
Time Frame: 8 month
Adenomas found with standard colonoscope / total of adenomas found X 100; adenomas found with Retroview™ scope / total of adenomas found X 100. The total of adenomas found will be determinated by the combination of both technics (standard colonoscope and Retroview™ scope)
8 month

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Lesion miss rate with the standard colonoscope and Retroview™ scope.
Time Frame: 8 month
Lesion miss rate: lesions missed / total of lesions (polyps and adenomas) X 100
8 month
Number and size of lesions (adenomas and polyps) detected with the standard colonoscope and Retroview ™ scope.
Time Frame: 8 month
The number and size of lesions will be described in each patient with both procedures. The size will be measure using a standard biopsy catheter as comparison method.
8 month

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Instituto Ecuatoriano de Enfermedades Digestivas

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

May 1, 2017

Primary Completion (ACTUAL)

July 31, 2017

Study Completion (ACTUAL)

August 31, 2017

Study Registration Dates

First Submitted

December 19, 2016

First Submitted That Met QC Criteria

May 13, 2017

First Posted (ACTUAL)

May 16, 2017

Study Record Updates

Last Update Posted (ACTUAL)

February 27, 2019

Last Update Submitted That Met QC Criteria

February 25, 2019

Last Verified

February 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DEC-19-2016

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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