Does Cap Assisted Colonoscopy Improve Detection of Adenomatous Polyps? (CAP Trial) (CAP)

Effectiveness of screening colonoscopy in cancer prevention relies on the detection and removal of adenomatous polyps. However, a substantial rate of adenomas is missed during a colonoscopy. It has been estimated that two thirds of missed adenomas are located on the proximal aspect of colonic folds. Attaching a transparent cap to the tip of a colonoscope may allow examination of the proximal aspect of colonic folds, and some early studies have suggested an increased polyp and adenoma detection using this technology. However, the studies have in part substantial methodological limitations (e.g. missing polyp histology, single endoscopist study, polyps not removed at the time of detection). Therefore, at this point it is unclear whether cap assisted colonoscopy may improve adenoma detection. The objective of this study is to evaluate whether cap assisted colonoscopy improves adenoma detection.

The investigators propose a two-center multiple endoscopists randomized controlled trial. Patients will be randomized to cap assisted colonoscopy or standard high definition white light colonoscopy. The cap is a 4mm commercially available transparent cap that is attached to the tip of the colonoscopy. Primary outcome measure is the adenoma detection rate (mean number of adenoma per patient). The investigators will assess and adjust for possible variables that can affect adenoma detection, including withdrawal time and quality of colon preparation. As a secondary outcome of interest the investigators will evaluate a possible learning curve effect among all endoscopists (a minimum of six) new to this method. In addition the investigators will evaluate whether cap assisted endoscopy improves real time prediction of polyp histology.

Study Overview

• Status: Completed
• Conditions: Adenomatous Polyps
• Intervention / Treatment: Device: Colonoscopy Cap

Detailed Description

All patients who present for a colonoscopy and meet inclusion and exclusion criteria will be asked to participate (see inclusion and exclusion criteria). All patients will undergo a regular bowel preparation with polyethylene glycol lavage (based on current standard of care) until clear rectal fluid is evacuated. Patients will be randomized to one of two groups:

1. Standard colonoscopy, or
2. Cap assisted colonoscopy. All colonoscopies will be performed using state of the art high-definition wide angle colonoscopy. The transparent cap, which is attached to the tip of the colonoscope, has a 4mm margin extending beyond the tip of the colonoscope. All patients will undergo a careful endoscopic examination. A timer will provide feedback on the time of insertion and the withdrawal time. Detected polyps will be assessed with standard white light and narrow band imaging to predict polyp histology (adenoma versus no adenoma), then resected and sent for histological evaluation according to standard of care. At least 8 experienced endoscopists at the participating centers will participate. Each endoscopist will perform at least 50 cap assisted colonoscopies as part of the study. Each endoscopist will be asked to complete a survey after 10 and after 50 cap assisted colonoscopies.

Patients will be randomized in blocks of four allocated to each examiner. The order of randomization will be computer generated. Information on randomization will be contained in sealed envelopes assigned to each examiner and individually opened immediately before the procedure after a patient's All participating endoscopist will fill out a questionnaire regarding the use of cap assistance colonoscopy after the initial 10 cap assisted colonoscopies and after at least 50 cap assisted cap colonoscopies. Endoscopists will also undergo a training session with respect to real time polyp diagnosis before study commencement and after each 20 colonoscopies enrollment.

• Study Type: Interventional
• Enrollment (Actual): 1148
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • New Hampshire
    • Lebanon, New Hampshire, United States, 03756
      • Dartmouth-Hitchcock Medical Center
  • Vermont
    • White River Junction, Vermont, United States, 05009
      • White River Junction VAMC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Any patient ≥ 50 years old and < 85 years old who presents for a colonoscopy with a potential for polyp resection and who does not meet any of the exclusion criteria mentioned below will be asked to participate

Exclusion criteria:

• Patients with known inflammatory bowel disease or active colitis
• Patients with familial adenomatous polyposis or other genetic syndromes that are associated with a high number of colonic polyps
• Patients who are receiving an emergency colonoscopy
• Poor general health (ASA class > 3)
• Patients on coumadin at the time of the procedure or with a coagulopathy and an elevated INR ≥ 1.5, or platelets < 50
• Patients who do not consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Standard colonoscopy
Active Comparator: Cap assisted colonoscopy; A transparent cap will be affixed to tip of the high-definition wide angle colonoscope.	Device: Colonoscopy Cap; 4mm transparent cap (Olympus) mounted to the tip of a colonoscope.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Number of Adenomas	Mean number of adenomas per patient in each group.	duration of colonoscopy

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adenoma Detection Rate	• Adenoma detection rate (ADR), % of patients with at least 1 adenoma	duration of colonoscopy
Advanced Adenoma Detection Rate	Proportion of patients with advanced adenomas	duration of colonoscopy
Quality of Bowel Preparation	Proportion of patients with a bowel preparation that was rated as good or excellent (four point scale that distinguishes the bowel prep as poor, fair, good or excellent).	duration of colonoscopy
Withdrawal Time	• Time taken for the withdrawal of the colonoscope from the cecum to anus among patients, who did not have any polyps.	time of colonoscope withdrawal
Ease of Terminal Ileum Intubation	• Proportion of patients, for whom intubation of the terminal ileum with the colonoscope was rated as "easy". Intubation could be rated by the endoscopist as "easy", "slightly difficult", "difficult", or "unable to intubate".	during colonoscopy
Real Time Prediction of Polyp Histology	Difference in recommended surveillance interval between real time polyp diagnosis and pathological diagnosis among patients with at least one diminutive polyp	duration of colonoscopy

Collaborators and Investigators

• Sponsor: White River Junction Veterans Affairs Medical Center
• Collaborators: Dartmouth-Hitchcock Medical Center
• Investigators: Principal Investigator: Heiko Pohl, White River Junction VAMC, Dartmouth Medical School

Publications and helpful links

General Publications

• von Renteln D, Kaltenbach T, Rastogi A, Anderson JC, Rosch T, Soetikno R, Pohl H. Simplifying Resect and Discard Strategies for Real-Time Assessment of Diminutive Colorectal Polyps. Clin Gastroenterol Hepatol. 2018 May;16(5):706-714. doi: 10.1016/j.cgh.2017.11.036. Epub 2017 Nov 23.
• von Renteln D, Robertson DJ, Bensen S, Pohl H. Prolonged cecal insertion time is associated with decreased adenoma detection. Gastrointest Endosc. 2017 Mar;85(3):574-580. doi: 10.1016/j.gie.2016.08.021. Epub 2016 Aug 31.
• Pohl H, Bensen SP, Toor A, Gordon SR, Levy LC, Berk B, Anderson PB, Anderson JC, Rothstein RI, MacKenzie TA, Robertson DJ. Cap-assisted colonoscopy and detection of Adenomatous Polyps (CAP) study: a randomized trial. Endoscopy. 2015 Oct;47(10):891-7. doi: 10.1055/s-0034-1392261. Epub 2015 Jun 30.

Study record dates

Study Major Dates

• Study Start: December 1, 2010
• Primary Completion (Actual): May 1, 2012
• Study Completion (Actual): May 1, 2012

Study Registration Dates

• First Submitted: January 19, 2012
• First Submitted That Met QC Criteria: August 29, 2013
• First Posted (Estimate): September 4, 2013

Study Record Updates

• Last Update Posted (Actual): September 25, 2018
• Last Update Submitted That Met QC Criteria: August 27, 2018
• Last Verified: August 1, 2018

More Information

Terms related to this study

• Keywords: colonoscopy; polyp detection; colon cancer screening; colon polyps; adenoma resection
• Additional Relevant MeSH Terms: Neoplasms by Histologic Type; Neoplasms; Neoplasms, Glandular and Epithelial; Pathological Conditions, Anatomical; Adenoma; Polyps; Adenomatous Polyps
• Other Study ID Numbers: DMS-22424