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Practice-Based Learning to Predict Polyp Histology at Colonoscopy: A Demonstration Project in Community Practice

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Colonic Polyps, Adenomatous Polyps

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Trial Information

Practice-Based Learning to Predict Polyp Histology at Colonoscopy: A Demonstration Project in Community Practice

A) Study Purpose and Rationale Most polyps removed at colonoscopy are small. The natural
history of these polyps is not understood completely, but the risk of subsequent cancer in
persons with small rectosigmoid adenomas may not be higher than in persons without
rectosigmoid adenomas [1]. With improvements in colonoscopic imaging, experienced
endoscopists can detect polyps in a large fraction of patients. Removal of all small polyps
followed by formal histopathological examination increases the costs associated with
colorectal cancer screening, and may increase the risk of complications, depending on the
technique that is used for polypectomy.

New technologies such as narrowband imaging (NBI) offer the possibility of in vivo
differentiation between adenomatous and hyperplastic polyps. Policies to leave in place
small polyps that appear to be hyperplastic, or to remove and discard small polyps after in
vivo histologic categorization without formal histopathology review could significantly
decrease the costs and potentially the risks of screening and surveillance colonoscopy.

Multiple studies have demonstrated the ability of experienced endoscopists to achieve high
accuracy in differentiating adenomatous from hyperplastic polyps using NBI [2, 3, 4, 5].
The level of confidence associated with in vivo histologic categorization of a particular
polyp is a valuable adjunct measure in determining subsequent clinical management.
Dissemination to the community setting of policies that promote in vivo histologic
categorization is likely to require practice-based learning.

B) Hypotheses The investigators hypothesize that community-based endoscopists can learn to
identify polyp histology at colonoscopy with the aid of NBI through the use of an
introductory didactic program, followed by practice based-learning, and that representative
learning curves can be generated that can serve as guidelines for wider dissemination.

C) Purpose The purpose of this study is to test an educational program combining a didactic
program followed by practice-based learning that is designed to allow community-based
endoscopists to become proficient at in vivo histologic characterization of small polyps
with the aid of NBI. This study will not require any changes in endoscopists' decisions
regarding the indications and methods for polypectomy.

This study will not address directly whether polyps predicted to be hyperplastic or even
diminutive adenomas should be left in place, or discarded and not submitted for formal
histopathological review.

D) Specific Aims This study has two primary and two secondary aims

1. One primary aim is to assess the proficiency of community-based endoscopists at ex vivo
histologic characterization of polyps using NBI based on photographs before and after a
didactic program designed to familiarize them with in vivo histologic characterization.

2. The central primary aim is to assess whether the currently designed program is
effective at training endoscopists to classify adenomatous vs. hyperplastic polyps in
practice with at least 90% accuracy.

3. A secondary aim is to characterize endoscopists' individual and group average learning
curves for in vivo histologic characterization using NBI during practice-based
learning, with attention to level of confidence, accuracy, sensitivity, specificity and
positive and negative predictive values.

4. Another secondary aim is to determine whether surveillance recommendations that would
be made based on in vivo histologic characterization using NBI are comparable to those
based on formal histopathological assessment.

E) Timeline for assessments:

Endoscopists' accuracy will be determined at three pre-specified points: after assessment of
50, 70 and 90 independent diminutive polyps (defined as <=5mm polyps, one per study
colonoscopy, with random selection in cases of >1 diminutive polyp per study colonoscopy).
We estimate that in order to assess 90 independent diminutive polyps, endoscopists will need
to participate for 6-12 months.

Inclusion Criteria:

- Community-based endoscopist who performs screening colonoscopy

Exclusion Criteria:

- Inability or lack of willingness to provide informed consent

Type of Study:


Study Design:

Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic

Outcome Measure:

Proportion of participants achieving 90% accuracy

Outcome Description:

Success for a participant was defined as achieving ≥90% accuracy in optical diagnosis of diminutive polyps. This was based on the last 30 consecutive independent diminutive polyps per participant at one of three pre-specified points (at polyp #50, 70 or 90).

Outcome Time Frame:

6-12 months depending on when an endoscopist has assessed 50, 70 and 90 independent diminutive polyps

Safety Issue:



United States: Institutional Review Board

Study ID:




Start Date:

March 2011

Completion Date:

Related Keywords:

  • Colonic Polyps
  • Adenomatous Polyps
  • Narrow band imaging
  • Screening colonoscopy
  • Histology
  • Colonic Polyps
  • Polyps
  • Adenomatous Polyps



Stanford University Stanford, California  94305
Huron Gastroenterology Ann Arbor, Michigan  48106