To investigate whether the International Society of Urological Pathology (ISUP) 2005 revision of the Gleason grading system has influenced the risk of biochemical recurrence (BR) after radical prostatectomy (RP), as the new guideline implies that some prostate cancers (PCa) previously graded as Gleason score (GS) 6 (3+3) are now considered as GS 7 (3+4).
A matched pair analysis was conducted. Two-hundred-and-fifteen patients with GS 6 or GS 7 (3+4) PCa on biopsies who underwent RP prior to December 31st, 2005 (pre-ISUP group), were matched 1:1 by biopsy GS, clinical tumour category, PSA, and margin status to patients undergoing RP between January 1st, 2008 and December 31st, 2011 (post-ISUP group). Patients were followed until BR defined as PSA ≥0. 2 ng/ml. Risk of BR was analysed in a competing risk model.
Median follow-up was 9. 5 years in the pre-ISUP group and 4. 8 years in the post-ISUP group. The 5-year cumulative incidences of BR were 34. 0% and 13. 9% (p<0. 0001) in the pre-ISUP and post-ISUP groups, respectively. The difference in cumulative incidence applied to both patients with GS 6 (p=0. 0002) and GS 7 (3+4) (p=0. 004). There was no difference in the 5-year cumulative incidence of BR between patients with pre-ISUP GS 6 and post-ISUP GS 7 (3+4) (p=0. 34). In a multiple Cox-proportional hazard regression model, ISUP 2005 grading was a strong prognostic factor for BR within 5 years of RP (hazard ratio = 0. 34; 95%CI: 0. 22-0. 54; p<0. 0001).
The revision of the Gleason grading system has reduced the risk of BR following RP in patients with biopsy GS 6 and 7 (3+4). This may have consequences when comparing outcomes across studies and historical periods and may affect future treatment recommendations. This article is protected by copyright. All rights reserved.
BJU international. 2016 Jan 28 [Epub ahead of print]
Kasper Drimer Berg, Frederik Birkebaek Thomsen, Camilla Nerstrøm, Martin Andreas Røder, Peter Iversen, Birgitte Grønkaer Toft, Ben Vainer, Klaus Brasso
Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Department of Pathology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.