Black men with prostate cancer may respond well to androgen deprivation therapy (ADT)-based regimens, but they are less likely to receive such therapy than non-Blacks, according to a new multi-institutional retrospective analysis. The study also found that black men with metastatic hormone-sensitive prostate cancer (mHSPC) are more likely to carry de novo metastases and have high volume disease.
“Treatment outcomes were very favorable with ADT-based regimens. The genomic landscape suggests different molecular profile relative to White patients with potential therapeutic implications,” the authors write. They also noted “a heterogenous management of this patient population in terms of systemic therapies used and the type and panel of the genomic testing performed.”
The study was published in The Oncologist. The lead author is Meredith N. Freeman of Tulane Cancer Center, Tulane University School of Medicine.
This finding comes as the outcomes for this disease have significantly improved as new drugs have been combined with ADT, but Black patients are not well represented in studies of those regimens. This retrospective analysis looked at baseline demographics, treatment patterns, genomic profiles, clinical outcomes including prostate-specific antigen response, time to castrate-resistant prostate cancer (CRPC), and subsequent treatments.
“To our knowledge, this is the largest cohort of Black patients reported since the incorporation of chemotherapy and novel hormonal therapies as the standard of care for patients with mHSPC,” the authors write.
A total of 107 patients, median age 64 years, 62% with de novo metastases at diagnosis and 64% with high-volume disease, were included. Twenty-nine patients (27%) were treated with androgen deprivation therapy (ADT) with and without first generation anti-androgens, while 20%, 38%, and 5% received chemotherapy, abiraterone, and enzalutamide, respectively.
The two-year survival rate was 93.3%, and estimated median overall survival of was 74.9 months (95% CI, 68.7–81.0). Most patients (90%) underwent germline testing, and the most frequent alterations were found within the DNA repair group of genes. Somatic testing revealed pathogenic alterations of interest, notably TP53 (24%) and CDK12 (12%).
Compared with non-Hispanic White men, non-Hispanic Black men have a much higher chance of developing prostate cancer and dying from the disease. It’s believed that socioeconomic factors, access to health care, baseline medical conditions, and underlying genetic factors may all play a role. It’s particularly disturbing, however, that Black men with low-risk prostate cancer have a higher risk of dying compared to non-Black men with similar disease burden.
The incidence of metastatic prostate cancer in the United States has been rising, from four percent in 2003 to eight percent in 2017. Up to 30% of patients initially diagnosed with and treated for localized prostate cancer develop metastases. With more treatment options now available, the five-year survival rate of metastatic prostate cancer has slightly increased in recent decades but still hovers around 30%.
The standard of care for prostate cancer treatment has significantly evolved over the last few years thanks to some phase III trial results, so that it now includes hormonal therapies or chemotherapy. When combined with ADT, these have improved all efficacy endpoints irrespective of tumor volume.
However, the study’s author’s note, Black patient representation in such studies was very low, ranging from just 1.4% to 9.6% of enrolled participants.
They write that, “This underrepresentation is ubiquitous across mainstream prostate cancer trials, as shown in an analysis of 72 global phases III and IV trials involving prostate cancer, in which an astounding 809,978 of 844,002 participants (96.0%) with available race data were White.”
Treatment is also skewed.
In this study, the researchers found that only a small fraction of patients (19%) who were treated for mHSPC after 2015 were offered ADT alone. However, real-world data suggest this is not typical, and that most patients with mHSPC are currently receiving ADT regimens without treatment intensification. Further, more of these patients are Black.