WATS3D: An Interobserver Study of Barrett's Esophagus-Associated Dysplasia Among Gastrointestinal Pathologists

INTRODUCTION: Wide-area transepithelial sampling with 3-dimensional computer-assisted analysis (WATS(3D)) has been shown to increase the detection rate of dysplasia (and intestinal metaplasia) in patients with Barrett's esophagus (BE). The purpose of this study was to evaluate the interobserver variability and accuracy of diagnosing BE-associated dysplasia in WATS(3D) specimens among gastrointestinal (GI) pathologists without prior experience with this technology. METHODS: Five GI pathologists underwent a 4-hour in-person (at microscope) and virtual training session and then evaluated digital images of discrete cellular foci from 60 WATS(3D) cases with BE (20 nondysplastic BE [NDBE], 20 low-grade dysplasia [LGD], and 20 high-grade dysplasia/esophageal adenocarcinoma [HGD/EAC]). Each case consisted of 1 hematoxylin and eosin-stained image (cell block), and 1 liquid cytology or papanicolaou-stained smear image (120 images in total). RESULTS: The overall kappa value among the 5 study pathologists was excellent (overall kappa = 0.93; kappa = 0.93 and 0.97 for cell block and smear specimens, respectively). There were no significant differences noted in kappa values in interpretation of the cell block vs smear specimens or in any of the individual diagnostic categories when the latter were evaluated separately. Furthermore, agreement was perfect (100%) regarding detection of neoplasia (either LGD, HGD, or EAC). Diagnoses were made with complete confidence in 91% of instances. DISCUSSION: We conclude that GI pathologists, without any prior experience in interpretation of WATS(3D) specimens, can undergo a short training session and then diagnose these specimens with a very high level of accuracy and reproducibility.