The impact of the 2005 International Society of Urological Pathology Gleason grading consensus on active surveillance for prostate cancer

Introduction Current treatment plans for localized prostate carcinoma (PC) are based on core needle biopsies (CNB) classified using the Gleason score (GS). Recently, many institutions have started using the latest version of International Society of Urological Pathology (ISUP) guideline revision from 2014 for PC grading. Interestingly, this adoption is occurring without first understanding whether the 2005 ISUP revisions had a positive clinical impact. CNB-based GS may underestimate tumor aggressiveness and, therefore, critically impact patient eligibility for active surveillance (AS). The 2005 ISUP recommendations bore a significant impact on the grading of Gleason 6 and 7 PCs - a range that is meaningful for AS. The objective of this study was to compare the concordance between GS in CNB and radical prostatectomy (RP) before and after the 2005 ISUP guideline revisions, with an emphasis on its clinical impact on AS. Material and methods This was a single-center, prospective observational study. CNB were performed in a standardized manner. GS of CNB and RP specimens were compared across three time periods: 1999-2005 (pre-revision), 2006-2007 (transitional period), and 2008-2015 (post-revision). AS is usually employed in patients with GS 6 or GS 7 PC. Thus, we therefore focused on the analysis of patients with CNBs of GS ≤7. Results Between 1999 and 2015, 380 men with GS ≤7 PC underwent RP at our institution (median age: 62y; median PSA: 5.8 ng/ml). Of these, 231 CNB specimens were classified as GS ≤6, while 149 were GS 7.46% (pre-revision), 43% (transitional), and 54% (post-revision) of CNB with original scores ≤6 were later upgraded in corresponding RP specimens (p <0.001). Conclusions The 2005 ISUP GS revisions did not lower the rates of GS upgrades in RP specimens when compared to corresponding initial CNBs. Thus, these revisions did not improve AS selection. Future advances in molecular diagnostics may provide additional valuable information that facilitates patient enrollment in AS programs.