Measuring Depth of Invasion of Submucosa- Invasive Adenocarcinoma in Esophageal Endoscopic Specimens: How Good are We?

AIMS Emerging data support that submucosa-invasive (pT1b) esophageal adenocarcinomas are cured via endoscopic resection provided that invasion measures ≤500 microns (μm), they lack other histologic features predictive of nodal metastasis, and have negative margins. Hence, pathologists' measurement of depth of submucosal invasion in endoscopic resections may dictate further management (i.e. endoscopic follow-up vs. esophagectomy). In this study, we assessed the interobserver agreement in measuring the depth of submucosal invasion in esophageal endoscopic resections. METHODS AND RESULTS Six subspecialized gastrointestinal (GI) pathologists from 5 academic centers independently measured the depth of submucosal invasion in μm from the deepest muscularis mucosae on 37 esophageal endoscopic resection slides (Round 1 scoring). A consensus meeting with a systematic approach for measuring and discussion of pitfalls was undertaken and re-measuring (Round 2 scoring) was done. Interobserver agreement was assessed by the `intraclass correlation coefficient (ICC) and Cohen's kappa statistics. A lack of agreement was seen amongst the six reviewers with a poor ICC for both rounds: 1 [0.40, 95% CI 0.26-0.56]; 2 [ 0.49 ,95%CI 0.34-0.63]. When measurements were categorized as 500 μm, the overall agreement amongst the 6 reviewers was only fair for both rounds: 1[Kappa 0.37, 95% CI 0.22-0.53]; 2 [Kappa 0.29, 95%CI 0.12- 0.46]. CONCLUSIONS Our study shows a lack of agreement among GI pathologists in measuring depth of submucosal invasion in esophageal endoscopic resections despite formulating a consensus approach for scoring. If important management decisions continue to be based upon this parameter, more reproducible and concrete guidelines are needed.