Time from definitive therapy to onset of metastatic disease predicts outcomes in men with metastatic hormone sensitive prostate cancer.

PURPOSE: Contemporary treatment for metastatic hormone sensitive prostate cancer (mHSPC) includes androgen deprivation therapy (ADT) plus abiraterone or docetaxel. While these intensified regimens have improved efficacy, they are also associated with increased cost and toxicities. Not all men with mHSPC may be candidates for these intensified regimens, yet there are no clinical models or biomarkers used to optimize treatment selection. Herein, we hypothesized that longer time from prior definitive therapy (DT), either radical prostatectomy, definitive radiotherapy, or both, to onset of metastatic disease is associated with improved survival outcomes in men with newly diagnosed mHSPC. METHODS: This multicenter retrospective study included men initiating systemic therapy with ADT for new mHSPC. Kaplan-Meier and COX proportional hazard models assessed time to metastatic castration-resistant prostate cancer (mCRPC) and overall survival (OS) by receipt of prior DT. RESULTS: Of the 253 men with new mHSPC, 115 (45%) had received prior DT. In a multivariate analysis, increasing years from DT to the start of ADT was an independent predictor of time to mCRPC (per year: hazard ratio 0.91 95% confidence interval 0.84-0.99, P = 0.020) and improved OS (per year: hazard ratio 0.87, 95% confidence interval 0.74-0.99, P = 0.0025) in patients with new mHSPC, and may assist with risk stratification in these patients at time of mHSPC. CONCLUSION: Time from DT to start of ADT is an independent predictor of time to mCRPC and OS in men with new mHSPC, and may assist with risk stratification of these patients for systemic therapy selection