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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01935180
Recruitment Status : Completed
First Posted : September 4, 2013
Results First Posted : May 30, 2017
Last Update Posted : September 25, 2018
Dartmouth-Hitchcock Medical Center
Information provided by (Responsible Party):
Dr. Heiko Pohl, White River Junction Veterans Affairs Medical Center

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.

Condition or disease Intervention/treatment Phase
Adenomatous Polyps Device: Colonoscopy Cap Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1148 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Screening
Official Title: Does Cap Assisted Colonoscopy Improve Detection of Adenomatous Polyps? (CAP Trial)
Study Start Date : December 2010
Actual Primary Completion Date : May 2012
Actual Study Completion Date : May 2012

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Colonoscopy

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.

Primary Outcome Measures :
  1. Mean Number of Adenomas [ Time Frame: duration of colonoscopy ]
    Mean number of adenomas per patient in each group.

Secondary Outcome Measures :
  1. Adenoma Detection Rate [ Time Frame: duration of colonoscopy ]
    • Adenoma detection rate (ADR), % of patients with at least 1 adenoma

  2. Advanced Adenoma Detection Rate [ Time Frame: duration of colonoscopy ]
    Proportion of patients with advanced adenomas

  3. Quality of Bowel Preparation [ Time Frame: duration of colonoscopy ]
    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).

  4. Withdrawal Time [ Time Frame: time of colonoscope withdrawal ]
    • Time taken for the withdrawal of the colonoscope from the cecum to anus among patients, who did not have any polyps.

  5. Ease of Terminal Ileum Intubation [ Time Frame: during colonoscopy ]
    • 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".

  6. Real Time Prediction of Polyp Histology [ Time Frame: duration of colonoscopy ]
    Difference in recommended surveillance interval between real time polyp diagnosis and pathological diagnosis among patients with at least one diminutive polyp

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   50 Years to 85 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

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

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 identifier (NCT number): NCT01935180

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United States, New Hampshire
Dartmouth-Hitchcock Medical Center
Lebanon, New Hampshire, United States, 03756
United States, Vermont
White River Junction VAMC
White River Junction, Vermont, United States, 05009
Sponsors and Collaborators
White River Junction Veterans Affairs Medical Center
Dartmouth-Hitchcock Medical Center
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Principal Investigator: Heiko Pohl White River Junction VAMC, Dartmouth Medical School

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Dr. Heiko Pohl, PI, White River Junction Veterans Affairs Medical Center Identifier: NCT01935180     History of Changes
Other Study ID Numbers: DMS-22424
First Posted: September 4, 2013    Key Record Dates
Results First Posted: May 30, 2017
Last Update Posted: September 25, 2018
Last Verified: August 2018
Keywords provided by Dr. Heiko Pohl, White River Junction Veterans Affairs Medical Center:
colon polyps
adenoma resection
colon cancer screening
polyp detection
Additional relevant MeSH terms:
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Adenomatous Polyps
Pathological Conditions, Anatomical
Neoplasms, Glandular and Epithelial
Neoplasms by Histologic Type