Black men with metastatic castration-resistant prostate cancer (mCRPC) have longer overall survival when treated with androgen receptor targeting agents (ARTAs) compared with non-Black men, according to study findings presented at the American Society of Clinical Oncology’s 2023 Genitourinary Cancers Symposium in San Francisco, California.
The study included 11,021 men who received treatment with ARTAs (abiraterone and enzalutamide) in the equal-access Veterans Health Affairs (VHA) medical system. Of these, 2550 (23.1%) identified as Black. The median overall survival was significantly longer for Black than non-Black patients (22.0 vs 20.0 months), a team led by Martin W. Schoen, MD, MPH, of the Saint Louis Veterans Affairs Medical Center and Saint Louis University in Missouri, and colleagues reported. On multivariable analysis, Black men had a significant 24% lower risk for death compared with non-Black men.
“One likely reason for longer survival is that Black veterans are more than 3 years younger when treated for mCRPC,” Dr Schoen said in an interview. “Younger men are able to receive treatment for longer periods of time and may have fewer adverse events. In this study, Black men were treated with either abiraterone or enzalutamide for an additional 1.7 months, which could lead to the differences in survival that we observed.”
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The mean age of the Black men was 72.6 years compared with 75.8 years for non-Black men. The median treatment duration was 15.8 months for Black men and 14.1 months for non-Black men.
Different patient populations might vary in their androgen signaling and development of resistance to ARTAs, which could explain the longer treatment duration and survival observed among Black men, Dr Schoen noted. Further, younger men are more likely to receive subsequent life-prolonging treatments for mCRPC, such as docetaxel or cabazitaxel.
Results also showed that Black men had a significantly higher median PSA level (60.3 vs 37.0 ng/mL), higher Charlson comorbidity index (4.5 vs 3.9), higher rate of cardiovascular disease (62.0% vs 59.8%), and lower mean body mass index (27.7 vs 28.4 kg/m2).
Survival among Black men also differed by treatment, with enzalutamide recipients having a significantly longer median survival compared with abiraterone recipients (24.5 vs 21.3 months).
The finding of a survival advantage for Black men is consistent with results of a study published in 2022 in Prostate Cancer and Prostatic Diseases. That study, by Daniel J. George, MD, of the Duke Cancer Institute at Duke University School of Medicine in Durham, North Carolina, and colleagues, included 2910 chemotherapy-naïve patients with mCRPC treated with abiraterone or enzalutamide at VHA facilities. Of these, 787 were Black and 2123 were White. Patients had a median follow-up of 19.0 and 18.7 months, respectively. On multivariable analysis, Black men had a significant 33% lower risk for death compared with White men, the investigators reported.
According to Dr Schoen, “Our study differs from the prior study by including veterans who were treated with ARTAs over a longer period of time, from May 2011 to June 2017 as well as veterans who have received chemotherapy. Additionally, we compared Black veterans to all veterans treated within the Veterans Affairs, not just White veterans. These differences resulted in one of the largest studies of Black men with mCRPC and corroborate the finding of improved survival in Black veterans identified by Dr George and his group.”
Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Reference
Cheranda N, Luo S, Sanfilippo M, Eisen SA, Schoen MW. Survival in Black and non-Black patients with metastatic prostate cancer. Presented at: ASCO GU 2023, San Francisco, California, February 16-18. Abstract 101.
George DJ, Ramaswamy K, Huang A, et al. Survival by race in men with chemotherapy-naïve enzalutamide- or abiraterone-treated metastatic castration-resistant prostate cancer. Prostate Cancer Prostatic Dis. 2022;25(3):524-530. doi:10.1038/s41391-021-00463-9
