Validation of International Society of Urological Pathology (ISUP) grading for prostatic adenocarcinoma in thin core biopsies using TROG 03.04 'RADAR' trial clinical data

In 2014 a consensus conference convened by the International Society of Urological Pathology (ISUP) adopted amendments to the criteria for Gleason grading and scoring (GS) for prostatic adenocarcinoma.

The meeting defined a modified grading system based on 5 grading categories (grade 1, GS 3+3; grade 2, GS 3+4; grade 3, GS 4+3; grade 4, GS 8; grade 5, GS 9-10). In this study we have evaluated the prognostic significance of ISUP grading in 496 patients enrolled in the TROG 03. 04 RADAR Trial. There were 19 grade 1, 118 grade 2, 193 grade 3, 88 grade 4 and 79 grade 5 tumours in the series, with follow-up for a minimum of 6. 5 years. On follow-up 76 patients experienced distant progression of disease, 171 prostate specific antigen (PSA) progression and 39 prostate cancer deaths. In contrast to the 2005 modified Gleason system (MGS), the hazards of the distant and PSA progression endpoints, relative to grade 2, were significantly greater for grades 3, 4 and 5 of the 2014 ISUP grading scheme. Comparison of predictive ability utilising Harrell's concordance index, showed 2014 ISUP grading to significantly out-perform 2005 MGS grading for each of the three clinical endpoints.

Pathology. 2015 Oct [Epub]

B Delahunt, L Egevad, J R Srigley, A Steigler, J D Murray, C Atkinson, J Matthews, G Duchesne, N A Spry, D Christie, D Joseph, J Attia, J W Denham

1Department of Pathology and Molecular Medicine, Wellington School of Medicine and Health Sciences, Wellington, New Zealand 2Department of Oncology - Pathology, Karolinska Institute, Stockholm, Sweden 3Department of Pathology and Molecular Medicine, McMaster University, Toronto, Canada 4School of Medicine and Public Health, University of Newcastle, Newcastle, NSW, Australia 5St Georges Cancer Care Centre, Christchurch 6Auckland Hospital, Auckland, New Zealand 7Peter MacCallum Cancer Centre, Melbourne, Vic 8Sir Charles Gairdner Hospital, Perth, WA 9Genesis Care, Tugun, Qld 10Hunter Medical Research Institute, Newcastle, NSW, Australia.

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