Clinical trial NCT01935180: Does Cap Assisted Colonoscopy Improve Detection of Adenomatous Polyps? (CAP Trial)
Official title: Does Cap Assisted Colonoscopy Improve Detection of Adenomatous Polyps? (CAP Trial)
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Adenomatous Polyps
Keywords: colon polyps
adenoma resection
colon cancer screening
colonoscopy
polyp detection
Lead sponsor: White River Junction Veterans Affairs Medical Center
Sponsor class: FED
Collaborators: name: Dartmouth-Hitchcock Medical Center
First posted: 2013-09-04
Enrollment: 1148
Sex: ALL
Minimum age (years): 50
Maximum age (years): 85
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: SCREENING

Brief summary: 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.

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.

Eligibility criteria: 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

Primary outcomes:
measure: Mean Number of Adenomas
timeFrame: duration of colonoscopy
Secondary outcomes:
measure: Adenoma Detection Rate
timeFrame: duration of colonoscopy
measure: Advanced Adenoma Detection Rate
timeFrame: duration of colonoscopy
measure: Quality of Bowel Preparation
timeFrame: duration of colonoscopy
measure: Withdrawal Time
timeFrame: time of colonoscope withdrawal
measure: Ease of Terminal Ileum Intubation
timeFrame: during colonoscopy
measure: Real Time Prediction of Polyp Histology
timeFrame: duration of colonoscopy
Other outcomes:
Locations:
city: Lebanon
country: United States
facility: Dartmouth-Hitchcock Medical Center
state: New Hampshire
city: White River Junction
country: United States
facility: White River Junction VAMC
state: Vermont
Study officials:
affiliation: White River Junction VAMC, Dartmouth Medical School
name: Heiko Pohl
role: PRINCIPAL_INVESTIGATOR
References:
citation: 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.
citation: 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.
citation: 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.