Application of a Prognostic Gleason Grade Grouping System to Assess Distant Prostate Cancer Outcomes.

Abstract

There is growing enthusiasm for the adoption of a novel grade grouping system to better represent Gleason scores. To evaluate the ability of prognostic Gleason grade groups to predict prostate cancer (PCa)-specific mortality (PCSM) and bone metastatic progression. We identified patients with PCa enrolled in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) registry across treatment strategies, including conservative and nondefinitive therapy. We examined the prognostic ability of Gleason grade groups to predict risk of PCSM and bone metastasis using the Kaplan-Meier method and unadjusted and adjusted Cox proportional hazards models. We identified 10529 men with PCa followed for a median of 81 mo (interquartile range 40-127), including 64% in group I (< 3 + 4); 17% in group II (3+4); 9% in group III (4+3); 6% in group IV (4+4); and 4% in group V (≥ 4 + 5). Relative to grade group I, the unadjusted risks of PCSM and bone metastasis were significantly associated with prognostic grade groupings for both biopsy and prostatectomy samples (all p<0.01). Pairwise comparisons within Gleason sums collapsed within grade group V were not significant; however, this analysis was limited by a small representation of men with Gleason pattern ≥ 4 + 5. The prognostic grade grouping system is associated with risk of PCSM and metastasis across management strategies, including definitive therapy, conservative management, and primary androgen deprivation. A five-level reporting system for prostate cancer pathology is associated with the risk of late prostate cancer endpoints.