Radium-223 for the treatment of metastatic castration-resistant prostate cancer: A window of opportunity

Context: The elimination of bone metastases, restoration and/or preservation of bone morphology and prevention and/or delay of skeletal events are a fundamental objective in the management of metastatic castration-resistant prostate cancer (mCRPC). Radium-223 is the first targeted alpha therapy with effects on bone that has been shown to increase survival in these patients, besides providing other bone-related benefits.

Objective: To analyze the impact of bone metastasis on mCRPC, and the benefits and the window of opportunity provided by radium-223 in the treatment of patients with mCRPC in the current treatment era.

Evidence acquisition: A bibliographic search of PubMed and Spanish and international congresses on radium-223 and other first-line treatments for mCRPC was performed. Recent guidelines and recommendations by experts were also consulted.

Summary of the evidence: Evidence for the mechanism of action of radium-223 widen its effects to the tumor bone environment. Survival of patients treated with radium-223 is higher in those with mild symptoms as opposed to those with moderate-severe symptoms. The presence of visceral metastases even in the early stages of mCRPC supports starting radium-223 therapy before the symptoms become clinically relevant. A 3-year study has confirmed its good safety profile. Changes in tALP and LDH may be useful markers for monitoring the treatment with radium-223, but they are not predictors of overall survival.

Conclusion: Radium-223 is a valuable therapeutic alternative in the treatment of patients with mCRPC in early stages of the disease, with a good safety profile. Its benefits extend to the bone environment.