Radium-223 Utilization Patterns and Outcomes in Clinical Practice.

ABSTRACT

INTRODUCTION: Radium-223 was approved for metastatic castration-resistant prostate cancer based on the ALSYMPCA trial. We characterize radium-223 treatment patterns and overall survival (OS) in a large equal access health system. METHODS: We identified all men within the Veterans Affairs (VA) Healthcare System who received radium-223 between January 2013 and September 2017. Patients were followed until death or last followup. We abstracted all treatments received prior to radium; no treatments after radium were abstracted. Our primary aim was understanding practice patterns, and secondary outcome was the association between treatment pattern and OS measured using Cox models. RESULTS: We identified 318 bone metastatic castration-resistant prostate cancer patients who received radium-223 within the VA Healthcare System. Of these patients 277 (87%) died during followup. The 5 predominant treatment patterns that encompassed 88% of patients (279/318) were 1) androgen receptor-targeted agent (ARTA)-radium, 2) docetaxel-ARTA-radium, 3) ARTA-docetaxel-radium, 4) docetaxel-ARTA-cabazitaxel-radium and 5) radium alone. Median OS was 11 months (95% CI 9.7-12.5). Men who received ARTA-docetaxel-radium had the worst survival. All other treatments had similar outcomes. Only 42% of patients completed the full 6 injections; 25% received only 1 or 2 injections. CONCLUSIONS: We identified the most common radium-223 treatment patterns and their association with OS within the VA population. The better survival in ALSYMPCA (14.9 months) vs our study (11 months) along with 58% of patients not receiving the full radium-223 course suggests radium is being used later in the disease course in the real world in a more heterogeneous population.