To address this, Ng and colleagues examined two datasets. The first was patients diagnosed with or who died from prostate cancer at 5 major medical centers in East London, United Kingdom, between 2008 and 2010. A key aspect is that all patients were covered under the National Health System in the United Kingdom and thus had equal insurance and thus equal access to care. Overall, they found that, depending on the hospital, Black men were between 50% and 3-fold more likely to be diagnosed with prostate cancer. However, the ethnic makeup of the men who died from prostate cancer matched the ethnic makeup of the men newly diagnosed. In short, though Black men were much more likely to be diagnosed, once diagnosed the risk of death appeared to be similar.
In the second dataset, the authors examined 425 men (103 Black and 322 White) with mCRPC in a single hospital in London from 1997 to 2016. The black men had lower hemoglobin levels and were suggestively more likely to have a performance status of 2 or more (19% vs. 9%, p=0.094) suggesting more advanced disease, but no other factors significantly differed by race. Rates of receiving chemotherapy were similar by race (73% for White and 70% for Black - keep in mind the dataset went back to 1997 when chemo was not yet established as standard-of-care for mCRPC). Unlike studies in the United States where Black men tend to be younger than White men, median ages of the groups were identical at 73. Importantly, the authors found that overall survival for the Black men was better (HR = 0.81, 95% CI 0.64 – 1.03, p=0.08) than the White men.
While the study Ng has limitations (small numbers, single-center for the mCRPC analyses, no multivariable analyses), it tells us some important points. First, the finding of more cancers but similar rates of long-term outcomes by race holds true outside the United States. Second, the finding of better outcomes among Black men with mCRPC vs. White men also holds true outside the United States. As such, though again this was a small study, it suggests that the increasingly clear associations seen in the United States likely apply elsewhere too.
Like any good study, while it answers some questions, it raises many more. Why are Black men more likely to have prostate cancer? Many (but not all) risk factors for getting a disease in the first place are associated with a more aggressive phenotype among those with the disease. The black race does not appear to follow this pattern. Why? Finally, why are Black men having better survival than those with mCRPC? Invariably the answers to these questions are complex. Clearly, access to care and appropriate treatment is key. However, even within these systems, these associations (more cancers, equal aggressiveness, but better survival in mCRPC) hold. Why? To what degree do lower socioeconomic status, differences in attitudes and beliefs about care, social determinants of health, social deprivation, systemic racism, and lifestyle factors contribute? To what degree do genetics contribute? Do gene and environment interactions contribute and how? The ultimate answer is likely quite complex. Nonetheless, while it is clear that much more research is needed, at the least we can conclude that 1) the associations seen in the United States are not unique and 2) a key step to reducing deaths from prostate cancer in Black men is to increase access to care.
Written by: Kenrick Ng1 2 Peter Wilson1 Katherine Mutsvangwa1 Luke Hounsome3 Jonathan Shamash4
- Department of Medical Oncology, Barts Health NHS Trust, London, UK.
- UCL Cancer Institute, University College London, London, UK.
- National Cancer Registration and Analysis Service, Public Health England, London, UK.
- Department of Medical Oncology, Barts Health NHS Trust, London, UK.
Read the Full-Text Article: Overall Survival of Black and White Men with Metastatic Castration-Resistant Prostate Cancer (mCRPC): A 20-Year Retrospective Analysis in the Largest Healthcare Trust in England