Daniel J. George, MD, Director of Genitourinary Oncology, Duke Cancer Institute, discusses the treatment of patients with metastatic castration-resistant prostate cancer (CRPC) with radium-223.

This is an exciting time in prostate cancer, George says, with the approval of radium-223 for the treatment of symptomatic metastatic CRPC. The FDA approval was based on the ALSYMPCA trial. In the trial, patients saw a significant improvement (over 3 months) to overall survival in favor of radium-223. Moving forward, radium-223 gives physicians an alternative option to chemotherapy and additional option for patients with bone metastases.

Radium-223 has a unique mechanism of action and could be used in patients with bone-predominant disease in place of chemotherapy. Though radium-223 will not be an adequate treatment for all prostate cancer patients, it will be for those in the last 18 months of survival, George says.

The majority of patients with mCRPC will be asymptomatic when initially diagnosed and would not be ideal candidates to receive radium-223. As patients develop symptoms, they become good candidates for the agent.

The biggest limit to radium-223 is the exposure to the drug and where it can be deposited. Unlike other similar agents, George says, radium-223 has a much shorter penetration.