Racial disparities exist between Black and White populations in many types of cancer. Researchers actively investigate disparities in the incidence and mortality rates of different cancers. In fact, many agencies supporting cancer research place a great deal of emphasis on funding projects that develop therapeutic approaches to reduce these racial disparities.
Compared to White men, Black men are more likely to be diagnosed with and die from prostate cancer, but little is known about how race impacts the response to prostate cancer treatment. While some of these differences are attributed to socioeconomic factors, evidence suggests that biological differences also play a role in the racial disparities associated with prostate cancer.
A new study published in JAMA Network Open investigated the impact of radiotherapy on prostate cancer outcomes in Black and White men. The researchers used data from clinical trials conducted over twenty years, selecting reports that administered radiotherapy to prostate cancer patients and enrolled many Black men.
The pooled analysis included data from seven published clinical trials which covered 8814 men (18.5% Black and 81.5% White) who, on average, were about 70 years old. The author indicated that Black men were more likely to have high-risk clinical characteristics such as elevated prostate-specific antigen (PSA) levels and Gleason scores, a measurement of how different prostate cancer cells look from healthy cells. These findings were in line with previous reports.
The study also demonstrated results that the authors referred to as “novel and unexpected”. These included the finding that Black men were less likely than White men to experience biochemical recurrence (BCR), a rise in PSA levels following radiotherapy. Metastasis, the spread of cancer to a distant site, was less frequent in Black men than White men. Prostate cancer-specific mortality was also less likely in Black than White men.
The authors noted some limitations to their study, including that race was self-reported and thus, may not capture a complete picture of biological differences among clinical trial participants. Additionally, while the initial radiotherapy treatment was standardized across trials, participants may have had follow-up treatments after the clinical trials that may have affected the long-term outcomes investigated.
Based on reduced recurrence, metastasis, and mortality, the authors conclude that, although Black men present with more advanced prostate cancer, they are likely to be more responsive to radiotherapy than White men. The authors also discuss the idea that their results “provide high-level evidence to question the belief that prostate cancer among Black men necessarily portends a worse prognosis compared with White men.”