Improved Survival With Prostate Radiation in Addition to Androgen Deprivation Therapy for Men With Newly Diagnosed Metastatic Prostate Cancer

Abstract

Purpose There is growing interest in the role of local therapies, including external beam radiotherapy (RT), for men with metastatic prostate cancer (mPCa). We used the National Cancer Database (NCDB) to evaluate the overall survival (OS) of men with mPCa treated with androgen deprivation (ADT) with and without prostate RT. Methods The NCDB was queried for men with newly diagnosed mPCa, all treated with ADT, with complete datasets for RT, surgery, prostate-specific antigen (PSA) level, Gleason score, and Charlson-Deyo comorbidity score. OS was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. Results From 2004 to 2012, 6,382 men with mPCa were identified, including 538 (8.4%) receiving prostate RT. At a median follow-up of 5.1 years, the addition of prostate RT to ADT was associated with improved OS on univariate (P < .001) and multivariate analysis (hazard ratio, 0.624; 95% CI, 0.551 to 0.706; P < .001) adjusted for age, year, race, comorbidity score, PSA level, Gleason score, T stage, N stage, chemotherapy administration, treating facility, and insurance status. Propensity score analysis with matched baseline characteristics demonstrated superior median (55 v 37 months) and 5-year OS (49% v 33%) with prostate RT plus ADT compared with ADT alone (P < .001). Landmark analyses limited to long-term survivors of ≥1, ≥3, and ≥5 years demonstrated improved OS with prostate RT in all subsets (all P < .05). Secondary analyses comparing the survival outcomes for patients treated with therapeutic dose RT plus ADT versus prostatectomy plus ADT during the same time interval demonstrated no significant differences in OS, whereas both therapies were superior to ADT alone. Conclusion In this large contemporary analysis, men with mPCa receiving prostate RT and ADT lived substantially longer than men treated with ADT alone. Prospective trials evaluating local therapies for mPCa are warranted.