Several recent studies on metastatic castration-resistant prostate cancer (mCRPC) demonstrated an improved overall survival for black vs. white men. Radium-223 is FDA approved for mCRPC based upon a survival benefit in the ALSYMPCA trial, where 94% of participants were white. We identified a real-world population of mCRPC patients who received radium-223 to compare differences in baseline characteristics and outcomes between black and non-black men.

We reviewed charts of all men who received radium-223 in the entire Veterans Affairs system. We compared treatment patterns and baseline characteristics between black and non-black men. We used Cox models to analyze predictors of time from radium-223 start to overall survival and time to skeletal related events.

A total of 318 patients treated with radium-223 were identified. There were 87 (27%) black patients. Median follow-up after radium-223 initiation was 25.3 months (IQR 13.8-37.1 months). Black men were younger compared to non-black men when starting radium-223 (median 67 vs 70 years, p<0.001) and had higher PSA (median 159.9 vs 90.2 ng/mL, p=0.014) and alkaline phosphatase (ALP) (median 163 vs 135 IU/L, p=0.017). A greater proportion of black men received docetaxel prior to radium-223 (77% vs. 55%, p<0.001). On multivariable analysis, black race was associated with a decreased risk of mortality from time of radium-223 initiation (HR 0.75, 95% CI 0.57-0.99, p=0.045).

Black men had longer overall survival vs. non-black men despite appearing to receive radium later in their disease course. Further studies are required to verify our findings and explore biologic differences between black and non-black men with mCRPC.

The Journal of urology. 2019 Sep 03 [Epub ahead of print]

Hanson Zhao, Lauren Howard, Amanda De Hoedt, Martha K Terris, Christopher Amling, Christopher Kane, Matthew Cooperberg, William Aronson, Zachary Klaassen, Thomas J Polascik, Adriana C Vidal, Stephen Freedland

Department of Surgery, Division of Urology, Cedars-Sinai Medical Center, Los Angeles, California., Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina., Division of Urology, Durham Veterans Affairs Health Care System, Durham, North Carolina., Section of Urology, Veterans Affairs Medical Center, Augusta, Georgia., Division of Urology, Department of Surgery, Oregon Health and Science University, Portland, Oregon., Urology Department, University of California San Diego Health System, San Diego, California., Department of Urology, UCSF Helen Diller Family Comprehensive Cancer Center, San Francisco, California., Department of Urology, UCLA School of Medicine, Los Angeles, California.