Clinical outcomes of patients with metastatic castration-resistant prostate cancer (mCRPC) receiving radium-223 (Ra-223) early versus late in the treatment sequence.

136 Background: Ra-223 is the only targeted alpha therapy shown to prolong overall survival (OS) in men with mCRPC. The purpose of this real-world study is to evaluate clinical outcomes of patients (pts) when Ra-223 is used early (second-line) or late (third or later lines) for mCRPC. Methods: We used administrative databases in Ontario (2012-2017) to estimate OS from start of second-line life prolonging therapy (LPT), event …