Impact of Gleason Pattern 5 on outcomes of patients with prostate cancer and iodine-125 prostate brachytherapy

BACKGROUND The Gleason grading system is a powerful predictor of prostate cancer (PCa) prognosis. Gleason scores (GS) of 8-10 are considered as a single high-risk grade category, and Gleason Pattern 5 (GP5) predicts biochemical recurrence. We report the clinical outcomes of patients treated with 125I prostate brachytherapy for clinically localized PCa and prognosis in the presence or absence of GP5. METHODS We enrolled 316 patients with T1c-T2N0M0 PCa and undergoing prostate brachytherapy treatment. All patients were followed up for ≥ 1 year. The primary endpoint was biochemical recurrence-free survival. Biochemical recurrence was defined by the Phoenix criteria. Survival curves were calculated by the Kaplan-Meier method, and the prognostic impact of biochemical recurrence was analyzed using a Cox proportional hazards model. RESULTS The 5-year biochemical recurrence-free survival rate for all patients was 95.2%, and according to the D'Amico risk classification criteria, the rates were 98.7% for patients in low-risk, 96.9% in intermediate-risk, and 81.1% in high-risk groups (P < 0.0001). The 5-year biochemical recurrence-free survival rates for patients with GS8 or GS9-10 were 87.7% and 61.5%, respectively (P = 0.0057). Multivariate analysis found that GS and clinical T stage were independent predictors of biochemical recurrence. CONCLUSIONS The presence of GP5 in GS9-10 prostate cancer has a worse prognosis than GS8 prostate cancer in the absence of GP5 for patients undergoing prostate brachytherapy.