Comparing virtual with conventional microscopy for the consensus diagnosis of Barrett's neoplasia in the AspECT Barrett's chemoprevention trial pathology audit

Aims: To compare the diagnostic accuracy of conventional versus virtual microscopy for the diagnosis of Barrett's neoplasia. Methods and results: Sixty-one biopsies from 35 ASPirin Esomeprazole ChemopreventionTrial (AspECT) trial patients were given a Barrett's neoplasia score (1-5) by a panel of five pathologists using conventional microscopy. Thirty-three biopsies positive for neoplasia were digitized and rescored blindly by virtual microscopy. Diagnostic reliability was compared between conventional and virtual microscopy using Fleiss' kappa. There was substantial reliability of diagnostic agreement (kappa = 0.712) scoring the 61 biopsies and moderate agreement scoring the subgroup of 33 'positive' biopsies with both conventional microscopy (kappa = 0.598) and virtual microscopy (kappa = 0.436). Inter-observer diagnostic agreement between two pathologists by virtual microscopy was substantial (kappa = 0.76). Comparison of panel consensus neoplasia scores between conventional and virtual microscopy was almost perfect (kappa = 0.8769). However, with virtual microscopy there was lowering of the consensus neoplasia score in nine biopsies. Conclusions: Diagnostic agreement with virtual microscopy compares favourably with conventional microscopy in what is recognized to be a challenging area of diagnostic practice. However, this study highlights possible limitations for this method in the primary diagnostic setting.