Global quantitative assessment of the colorectal polyp burden in familial adenomatous polyposis by using a web-based tool

Abstract

Background: Accurate measures of the total polyp burden in familial adenomatous polyposis (FAP) are lacking. Current assessment tools include polyp quantitation in limited-field photographs and qualitative total colorectal polyp burden by video.

Objective: To develop global quantitative tools of the FAP colorectal adenoma burden.

Design: A single-arm, phase II trial.

Patients: Twenty-seven patients with FAP.

Intervention: Treatment with celecoxib for 6 months, with before-treatment and after-treatment videos posted to an intranet with an interactive site for scoring.

Main outcome measurements: Global adenoma counts and sizes (grouped into categories: <2 mm, 2-4 mm, and >4 mm) were scored from videos by using a novel Web-based tool. Baseline and end-of-study adenoma burden results were summarized by using 5 models. Correlations between pairs of reviewers were analyzed for each model.

Results: Interobserver agreement was high for all 5 measures of polyp burden. Measures that used both polyp count and polyp size had better interobserver agreement than measures based only on polyp count. The measure in which polyp counts were weighted according to diameter, calculated as (1) × (no. of polyps <2 mm) + (3) × (no. of polyps 2-4 mm) + (5) × (no. of polyps >4 mm) had the highest interobserver agreement (Pearson r = 0.978 for two gastroenterologists, 0.786 and 0.846 for the surgeon vs each gastroenterologist). Treatment reduced the polyp burden by these measurements in 70% to 89% of patients (P < .001).

Limitations: Phase II study.

Conclusion: This novel, Web-based polyp scoring method provides a convenient and reproducible way to quantify the global colorectal adenoma burden in FAP patients and a framework for developing a clinical staging system for FAP.

Copyright © 2013 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Figures

Figure 1

Web-based tool for scoring polyp burden. A. Picture of the scoring screen for the web-based tool. B–D. Higher-magnification views of the components of the scoring screen: the scoring card (B), streaming video (C), and list of videos (D).

Figure 2

Study flow diagram. FAP, familial adenomatosis polyposis.

Figure 3

Cumulative distribution of per cent changes in total polyp burden following 6 months of celecoxib treatment by reviewer and polyp burden measure. In the top 3 panels, total polyp burden was calculated as follows, where CS, CM, and CL were the counts of small (<2 mm), medium (2–4 mm), and large (>4 mm) polyps, respectively: equally spaced “ES”, polyp burden = (1×CS)+(2×CM)+(3×CL); mid-range “MR”, polyp burden = (1×CS)+(3×CM)+(5×CL); and bottom-range “BR”, polyp burden = (1×CS)+(2×CM)+(4×CL). TC “Total Count” indicates that total polyp burden was determined by summing the counts for polyps in all 3 size groups; TC2 “Count 2” indicates that total polyp burden was determined by summing the counts for medium (2–4 mm) and large (>4 mm) polyps only.