Optimization of the 2014 Gleason grade grouping in a Canadian cohort of patients with localized prostate cancer

Objectives To evaluate the five‐tier Gleason grade group (GG) scoring of prostate cancers adopted by the International Society of Urology Pathology (ISUP) in 2014, and to propose modifications to optimize its performance. Patients and Methods Data were obtained from PROCURE, a prospective cohort of patients with localized prostate cancer undergoing radical prostatectomy in Québec, 2006–2013. Surgical specimens were evaluated by genitourinary pathologists using 2014 ISUP criteria. Treatment failure was defined as biochemical recurrence and/or initiation of secondary, non‐adjuvant therapy. Analyses were conducted using Kaplan–Meier methods, log‐rank tests, Cox proportional hazards models and Harrell's concordance indices. Results A total of 1 917 patients were included, with a median follow‐up of 69 months. The 5‐year treatment failure rates were 9.6%, 23.5%, 43.1%, 52.6% and 84.3% in GG1–5, respectively (P