Retroview™ Colonoscope and Lesion Detection Rate

Colonic Neoplasms Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03155165
• Other study ID #: DEC-19-2016
• Status: Completed
• Start date: May 1, 2017
• Est. completion date: August 31, 2017

Study information

• Verified date: February 2019
• Source: Instituto Ecuatoriano de Enfermedades Digestivas
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 100
• Est. completion date: August 31, 2017
• Est. primary completion date: July 31, 2017
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years to 80 Years

Eligibility

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.

Related Conditions & MeSH terms

• Colonic Neoplasms

Intervention

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.

Locations

Country	Name	City	State
Ecuador	Ecuadorian Institute of Digestive Diseases, Omnihospital	Guayaquil	Guayas

Sponsors (1)

Lead Sponsor	Collaborator
Instituto Ecuatoriano de Enfermedades Digestivas

Country where clinical trial is conducted

Ecuador, 

References & Publications (23)

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Fatima H, Rex DK, Rothstein R, Rahmani E, Nehme O, Dewitt J, Helper D, Toor A, Bensen S. Cecal insertion and withdrawal times with wide-angle versus standard colonoscopes: a randomized controlled trial. Clin Gastroenterol Hepatol. 2008 Jan;6(1):109-14. Ep — View Citation

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Hewett DG, Rex DK. Miss rate of right-sided colon examination during colonoscopy defined by retroflexion: an observational study. Gastrointest Endosc. 2011 Aug;74(2):246-52. doi: 10.1016/j.gie.2011.04.005. Epub 2011 Jun 15. — View Citation

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McGill SK, Kothari S, Friedland S, Chen A, Park WG, Banerjee S. Short turn radius colonoscope in an anatomical model: retroflexed withdrawal and detection of hidden polyps. World J Gastroenterol. 2015 Jan 14;21(2):593-9. doi: 10.3748/wjg.v21.i2.593. — View Citation

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Rex DK, Cutler CS, Lemmel GT, Rahmani EY, Clark DW, Helper DJ, Lehman GA, Mark DG. Colonoscopic miss rates of adenomas determined by back-to-back colonoscopies. Gastroenterology. 1997 Jan;112(1):24-8. — View Citation

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Waye JD, Heigh RI, Fleischer DE, Leighton JA, Gurudu S, Aldrich LB, Li J, Ramrakhiani S, Edmundowicz SA, Early DS, Jonnalagadda S, Bresalier RS, Kessler WR, Rex DK. A retrograde-viewing device improves detection of adenomas in the colon: a prospective eff — View Citation

Winawer SJ, Zauber AG, Ho MN, O'Brien MJ, Gottlieb LS, Sternberg SS, Waye JD, Schapiro M, Bond JH, Panish JF, et al. Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N Engl J Med. 1993 Dec 30;329(27):1977-81 — View Citation

* Note: There are 23 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Polyp detection rate with the standard colonoscope and Retroview™ scope.	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
Primary	Adenoma detection rate with the standard colonoscope and Retroview™ scope.	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	Lesion miss rate with the standard colonoscope and Retroview™ scope.	Lesion miss rate: lesions missed / total of lesions (polyps and adenomas) X 100	8 month
Secondary	Number and size of lesions (adenomas and polyps) detected with the standard colonoscope and Retroview ™ scope.	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