Emerging role of Radium-223 in the growing therapeutic armamentarium of metastatic castration-resistant prostate cancer.

INTRODUCTION: During the last few years, the therapeutic armamentarium of castration resistant prostate cancer (mCRPC) has been enriched with the introduction of new effective therapies with proved survival benefit and quality of life gain, including cabazitaxel, abiraterone, enzalutamide, and Radium-223. Areas covered: Bone metastases represent a substantial cause of morbidity in mCRPC with a high rate of related skeletal events (SREs). In case of multifocal pain due to diffuse osteoblastic metastases, treatment with bone-targeting radiopharmaceutical agents can provide palliation from pain. Radium-223, a calcium-mimetic, is the first α-particle emitting radiopharmaceutical that prolonged overall survival, delayed symptomatic skeletal events and improved quality of life in mCRPC. Expert opinion: In this therapeutic scenario, no clear evidences support the best way to sequence these available agents and there is an urgent need for prospective studies to define it. 223Ra is a firmly established therapeutic option in CRPC with symptomatic bone metastases and no visceral/bulky nodal involvement, with an undeniable advantage over new hormonal agents, given its peculiar mechanism of action. Current ongoing randomized clinical trials will clarify the optimal use of this effective therapy in the therapeutic armamentarium of CRPC either alone or combined with other new approved agents and whether there is a role in patients with asymptomatic disease.