Interobserver reproducibility of Gleason grading in prostate biopsy samples

Abstract

Introduction: Gleason grading is the most common method of prostate cancer classification. Aim: The aim of the authors was to assess the reproducibility of Gleason grading among pathologists using the same needle biopsy samples. Method: 23 pathologists examined 37 prostate cancer biopsies stained with hematoxylin and eosin. Gleason scores were categorised into 4 groups (2–4, 5–6, 7 and 8–10). Kappa statistics were used to reflect interobserver agreement. Results: Considering all participating pathologists, grouping into one of the 4 categories resulted in an overall kappa value of 0.49. For the individual categories, the worst agreement (kappa = 0.15) was seen with well differentiated carcinomas, and the best (kappa = 0.65) with poorly differentiated ones. Conclusions: These results suggest that Gleason grading in biopsy samples is moderately reproducible. The kappa values vary according to the differentiation of the cancer, and there is not much difference between the results of the present study and those published in the literature. To increase reproducibility, trainings should be organised, and this could improve the quality of grading. Orv. Hetil., 2013, 154, 1219–1225.