Gleason scoring of prostatic carcinoma: impact of a web-based tutorial on inter- and intra-observer variability

A total of 40 cases of prostatic adenocarcinomas were scored independently by four pathologists using the Gleason scoring system. After attending a web-based tutorial, the scoring was repeated by all. Consensus scores were obtained by simultaneous viewing of each case in a multihead microscope by all four pathologists. The scores were then compared. The pretutorial kappa (kappa) values ranged from 0.36 to 0.64 with an average of 0.459. After the tutorial, the kappa values ranged from 0.44 to 0.678 with the average kappa value increasing to 0.538, thus indicating an improvement in the agreement. The intraobserver agreement ranged from 0.435 to 0.788. We conclude that web-based tutorials with emphasis on images developed by experts serve to achieve an uniformity in reporting.