Reproducibility of Villous Component and High Grade Dysplasia in Colorectal Adenomas < 1 cm: Implications for Endoscopic Surveillance
Dipti Mahajan, Erinn Downs-Kelly, Xiuli Liu, Rish Pai, Deepa T Patil, Lisa Rybicki, Ana Bennett, Thomas Plesec, Oscar Cummings, Douglas K Rex, John R Goldblum. Cleveland Clinic, Cleveland, OH; Indiana University Hospital, Indianapolis, IN
Background: In patients with 1 or 2 adenomas < 1 cm, the presence of high grade dysplasia (HGD) or villous component (VC) define an advanced adenoma (AA). Current consensus guidelines recommend that patients with AA undergo more intense post-polypectomy surveillance. In these clinical situations, the interobserver reliability in determining VC and HGD would play a major role in the credibility of these consensus guidelines. Therefore, the purpose of this study was to evaluate interobserver variability of VC and HGD in polyps < 1 cm before and after the development of consensus criteria among gastrointestinal (GI) pathologists.
Design: 5 expert GI pathologists evaluated 107 colorectal adenomas < 1 cm independently and classified them into tubular adenomas (TA), or adenomas with a villous component (A-VC) and into low grade dysplasia or HGD. After round 1; a consensus conference was held and consensus criteria for VC and HGD were developed by group review. The same set of 107 slides were re-reviewed independently by the same 5 GI pathologists. Interobserver variability utilizing kappa statistical analysis before and after the application of consensus criteria was assessed. A one-sided z-test was used to determine if kappa scores increased after the consensus conference.
Results: Interobserver agreement both before and after the consensus conference was poor for assessment of A-VC, HGD and AA (either A-VC or HGD).
|Feature||Kappa||P||95% CI||Interobserver agreement*|
|A-VC||0.21||<0.001||0.15 - 0.27||Poor|
|HGD||0.26||<0.001||0.20 - 0.32||Poor|
|AA||0.29||<0.001||0.23 - 0.35||Poor|
|A-VC||0.37||<0.001||0.31 - 0.43||Poor|
|HGD||0.31||<0.001||0.25 - 0.37||Poor|
|AA||0.34||<0.001||0.28 - 0.40||Poor|