[836] Standardization of Gleason Grading among 337 Pathologists

Lars Egevad, Ferran Algaba, Daniel M Berney, Liliane Boccon-Gibod, Eva Comperat, Andrew J Evans, Rainer Grobholz, Glen Kristiansen, Cord Langner, Antonio Lopez-Beltran, Rodolfo Montironi, Pedro Oliveira, Ben Vainer, Murali Varma, Philippe Camparo. Karolinska Institutet, Stockholm, Sweden; Fundacio Puigvert-University Autonomous, Barcelona, Spain; St Bartholomew's Hospital, London, United Kingdom; Hopital Armand Trousseau, Paris, France; Hopital La Pitié-Salpetrière, Paris, France; University of Toronto, Toronto, Canada; Kantonsspital Aarau, Aarau, Switzerland; University Hospital, Bonn, Germany; Medical University, Graz, Austria; Cordoba University Medical School, Cordoba, Spain; Polytechnic University of the Marche Region, Ancona, Italy; Hospital da Luz, Lisboa, Portugal; Rigshospitalet, Copenhagen, Denmark; University Hospital of Wales, Cardiff, United Kingdom; Hopital Foch, Paris, France

Background: A key decision in the 2005 ISUP revision of the Gleason grading of prostate cancer was to always include the highest grade in the Gleason score (GS) of needle biopsies (NBX), even if only a minute focus. This may have caused a reporting shift from GS 6 to 7 or higher. Our aim was to analyze contemporary reporting of GS 6 vs. 7 among a large group of pathologists.
Design: A panel of 15 experts in urological pathology reviewed 25 digitized NBX with GS 6-7 cancer and reached 2/3 consensus in 15 cases. The expert diagnosis was GS 3+3, 3+4 and 4+3 in 6, 7 and 2 cases, respectively. A total of 85 microphotographs of single cores from these 15 cases were published on a website and members of the European Network of Uropathology (ENUP) were invited to report GS.
Results: Among 618 ENUP members, 337 (54.5%) replies were received from 19 countries. There was agreement between experts and the majority member vote in 12 of 15 cases, while members upgraded from GS 3+4 to 4+3 in 2 cases and from 4+3 to 4+4 in 1 case. Mean GS of expert consensus and member grading was 6.60 and 6.74, respectively (p <0.001). Mean member GS was higher than consensus GS in 9 of 15 cases. A Gleason pattern (GP) 5 was reported by at least one member in 10 of 15 cases with mean 2.0%, range 0.3% - 5.6% per case. The agreement between consensus and member GS was 58.2%-89.3% (mean 71.4%) in GS 6 cases and 46.3%-63.8% (mean 56.4%) in GS 7 cases (p = 0.009), overall 46.3% to 89.3% (mean 62.4%).
Conclusions: There is disagreement among pathologists on how to report GS 6-7 cases. While undergrading used to be prevalent in the pathology community, some pathologists now tend to assign a high GS even to cases diagnosed as GS 6 by experts. The detection threshold for minimal foci of GP 4 and 5 in NBX needs to be better defined. Image libraries reviewed by experts may be useful for standardization.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 115, Wednesday Morning

 

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