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Retroview™ Colonoscope and Lesion Detection Rate

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ClinicalTrials.gov Identifier: NCT03155165
Recruitment Status : Recruiting
First Posted : May 16, 2017
Last Update Posted : May 16, 2017
Sponsor:
Information provided by (Responsible Party):
Instituto Ecuatoriano de Enfermedades Digestivas

Brief 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.

Condition or disease Intervention/treatment
Colonic Neoplasms Device: Retroview™ colonoscope

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
Estimated Enrollment : 100 participants
Observational Model: Case-Only
Time Perspective: Cross-Sectional
Official Title: Retroview™ vs. Conventional Colonoscopy: it is Time to Change?
Actual Study Start Date : May 1, 2017
Estimated Primary Completion Date : July 2017
Estimated Study Completion Date : August 2017

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Colonoscopy

Group/Cohort Intervention/treatment
Group A
Patients that have a polyp already seen in a previous colonoscopy and the colonoscopy is indicated for polypectomy.
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
The rest of colonoscopies indicated .
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.




Primary Outcome Measures :
  1. 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)

  2. 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)


Secondary Outcome Measures :
  1. 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

  2. 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.


Biospecimen Retention:   Samples Without DNA
Histology sample of polypectomies


Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
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.
Criteria

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.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03155165


Contacts
Contact: Carlos A Robles-Medranda, MD (+593) 989158865 carlosoakm@yahoo.es
Contact: Manuel Valero, MD (+593) 981765456 valero.manuel@hotmail.com

Locations
Ecuador
Ecuadorian Institute of Digestive Diseases, Omnihospital Recruiting
Guayaquil, Guayas, Ecuador, 090505
Contact: Carlos A Robles-Medranda, MD    +593989158865    carlosoakm@yahoo.es   
Contact: Manuel Valero, MD    +59342109180 ext 105    valero.manuel@hotmail.com   
Principal Investigator: Carlos A Robles-Medranda, MD         
Sub-Investigator: Manuel Valero, MD         
Sub-Investigator: Hannah P Lukashok, MD         
Sponsors and Collaborators
Instituto Ecuatoriano de Enfermedades Digestivas
Investigators
Principal Investigator: Carlos A Robles-medranda, MD Ecuadorian Institute of Digestive Diseases

Publications of Results:

Responsible Party: Instituto Ecuatoriano de Enfermedades Digestivas
ClinicalTrials.gov Identifier: NCT03155165     History of Changes
Other Study ID Numbers: DEC-19-2016
First Posted: May 16, 2017    Key Record Dates
Last Update Posted: May 16, 2017
Last Verified: May 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided

Keywords provided by Instituto Ecuatoriano de Enfermedades Digestivas:
Colonoscopy, Retroview™ colonoscope, retrofex colonoscopy

Additional relevant MeSH terms:
Colonic Neoplasms
Colorectal Neoplasms
Intestinal Neoplasms
Gastrointestinal Neoplasms
Digestive System Neoplasms
Neoplasms by Site
Neoplasms
Digestive System Diseases
Gastrointestinal Diseases
Colonic Diseases
Intestinal Diseases