Do Black Men with Metastatic Castration-Resistant Prostate Cancer Have Worse Outcomes Than White Patients? A Nationwide VA Study
Abstract
Black men have a 67% higher prostate cancer risk than white men and over twice the mortality. While, in general, black men have reduced access to care, within an equal access setting, we found they had higher-grade disease at diagnosis and higher risk of cancer recurrence after surgery. These biological differences by race may play a role in how patients respond to prostate cancer therapy. Indeed, recent studies presented at ASCO and other conferences suggest that, compared to white men, black men with metastatic castration-resistant prostate cancer (mCRPC) may actually have better outcomes. In one study, men with mCRPC were treated with abiraterone, and it was found that black men had a better disease progression outcome (16.6 months) compared to white men (11.5 months). The second study analyzed overall survival data in mCRPC patients from nine phase III trials conducted between 1999 and 2014, in which 7,528 white men and 500 black men were randomly assigned to receive docetaxel/prednisone alone or in combination with other drugs. An analysis of the nine trials found that black men with mCRPC had a 20% lower risk of death vs. white men. Of note, black men in these trials were younger, had poorer performance statuses, and had higher PSA and testosterone levels. The final study examined men with mCRPC in a subset analysis of a randomized clinical trial of sipuleucel-T (Provenge) and found that black men may respond better to anti-cancer immunotherapy vs. white men. However, these data conflict with population-level data in mCPRC men that continue to suggest worse outcomes for black men. Thus, whether these worse outcomes at the population level are due to unmeasured confounding, the fact that black men are less likely to receive life-prolonging therapies and/or to adhere to the therapies prescribed, or poorer response to these treatments is unknown. This represents a major gap. Our objective is to create the largest cohort ever developed for prostate cancer health disparities. Our primary focus is to test whether black men with mCRPC will have similar responses to modern mCRPC therapies, but worse compliance. Using the power of the Department of Veterans Affairs (VA) Health System, we will have access to a dataset with ~5,000,000 men followed for up to 20 years. This dataset will allow us to abstract key data, including therapy for mCRPC, race, obesity, socioeconomic status, distance to closest health care center, serum PSA, hemoglobin, Alk phos, PC grade, prior PC treatments, and compliance (measured as how timely prescriptions are refilled). Finally, as our group has extensive experience mining VA data, it is anticipated that further mining of this dataset, along with the diagnostic tissue, will provide valuable insights into prostate cancer biology in general, as well as specifically for black men. In summary, our proposed study is important and will add a new layer of understanding of prostate cancer racial disparities and life-prolonging therapies for mCRPC because (1) it will examine whether drug efficacy differs by race (if true, interventions directed at informing clinicians about care for black men with mCRPC could be implemented); (2) if our study finds that drug compliance influences prognosis for black men, it would mean that, even in an equal access care setting, black men will need to be followed up, e.g., via phone call reminders to fill their prescriptions, schedule a doctor’s appointment, etc.; (3) after accounting for compliance, if we observe that black men with mCRPC have better outcomes than white men, this will help clinicians decide the best drug to give to a man newly diagnosed with mCRPC based on race.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 19, 2019
- Source ID
- W81XWH1910748
Entities
People
- Adriana Vidal
Organizations
- Cedars-Sinai Medical Center
- United States Army