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

BACKGROUND: There is growing enthusiasm for the adoption of a novel grade grouping system to better represent Gleason scores. OBJECTIVE: To evaluate the ability of prognostic Gleason grade groups to predict prostate cancer (PCa)-specific mortality (PCSM) and bone metastatic progression. DESIGN, SETTING, AND PARTICIPANTS: 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. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: 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. RESULTS AND LIMITATIONS: 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. CONCLUSIONS: 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. PATIENT SUMMARY: A five-level reporting system for prostate cancer pathology is associated with the risk of late prostate cancer endpoints.