The reasons behind variation in Gleason grading of prostatic biopsies: areas of agreement and misconception among 266 European pathologists (Histopathology, 2014)
Berney DM, Algaba F, Camparo P, Compérat E, Griffiths D, Kristiansen G, Lopez-Beltran A, Montironi R, Varma M, Egevad L.
AIMS: The Gleason scoring system underwent revision at the International Society of Urological Pathology (ISUP) conference in 2005. It is not known how uropathologists have interpreted its recommendations.
METHOD AND RESULTS: A web-based survey to European Network of Uropathology members received replies from 266 pathologists in 22 countries. Eighty-nine per cent claimed to follow ISUP recommendations. Key areas of disagreement included the following. Smoothly rounded cribriform glands were assigned Gleason pattern (GP) 3 by 51% and GP 4 by 49%. Necrosis was diagnosed as GP 5 by 62%. Any amount of secondary pattern of higher grade in needle biopsies was included in the Gleason score by 58%. Tertiary GP of higher grade on needle biopsies was included in the Gleason score by only 58%. If biopsy cores were embedded separately, only 56% would give a Gleason score for each core/slide examined; 68% would give a concluding Gleason score and the most common method was a global Gleason score (77%). Among those who blocked multiple biopsy cores together, 46% would only give an overall Gleason score for the case.
CONCLUSIONS: Misinterpretation of ISUP 2005 is widespread, and may explain the variation in Gleason scoring seen. Clarity and uniformity in teaching ISUP 2005 recommendations is necessary.