Definitive radiotherapy for prostate cancer benefits Black men more than white men
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Although Black men presented with more aggressive prostate cancer, they experienced better outcomes with definitive radiotherapy compared with white men, according to results of a meta-analysis published in JAMA Network Open.
Other determinants of outcome, including access to care, are key to achieving racial equity in prostate cancer care, researchers noted.
Rationale
“Multiple publications have demonstrated overall worse outcomes for Black men with prostate cancer compared with white men with prostate cancer. However, this could simply reflect issues with access to care and delivery of standard-of-care treatments,” Amar U. Kishan, MD, researcher in the department of radiation oncology at University of California, Los Angeles, told Healio. “We sought to rigorously examine this by looking at randomized trial data, as patients enrolled on clinical trials are at least guaranteed to have similar treatments regardless of race, as well as similar follow-up and similar thresholds for diagnosing treatment failure.”
Methodology
The meta-analysis included 8,814 men (mean age, 69.1 years; 81.5% white) with localized prostate cancer included in randomized clinical trials evaluating definitive radiotherapy with or without androgen deprivation therapy.
Main outcomes included prostate cancer-specific mortality and prostate cancer recurrence.
Key findings
At median follow-up of 10.6 years, the analysis showed that although Black men more likely had high-risk prostate cancer features at study enrollment, they had a significantly lower likelihood of biochemical recurrence (subdistribution HR [sHR] = 0.88; 95% CI, 0.58-0.91), distant metastases (sHR = 0.72; 95% CI, 0.58-0.91) and prostate cancer-specific mortality (sHR = 0.72; 95% CI, 0.54-0.97).
Moreover, in a meta-analysis adjusted for age, initial PSA level, T category, Gleason score and treatment strategy, Black race remained significantly associated with improvements in biochemical recurrence (sHR = 0.79; 95% CI, 0.72-0.88), distant metastases (sHR = 0.69; 95% CI, 0.55-0.87) and prostate cancer-specific mortality (sHR = 0.68; 95% CI, 0.5-0.93).
Researchers observed no significant differences in all-cause mortality between Black and white men (HR = 0.99; 95% CI, 0.92-1.07).
“Although Black men had more aggressive disease at the time of enrollment on clinical trials — which could be explained by disparities in access to care — after receiving standard-of-care therapy, their outcomes were at least equal to, if not better than, those of their white counterparts. This applied to both very early treatment outcomes, such as early progression, and to late treatment outcomes, such as mortality from the cancer,” Kishan said.
Implications
“Access to care and delivery of standard of care needs to be a major focus if we are to reduce the disparities in prostate cancer outcomes between Black and white men,” Kishan said. “We also need to be wary of unnecessarily overtreating Black men or thinking that Black men are destined to have worse outcomes once they are diagnosed with prostate cancer. We and others hope to understand if there is an explanation for the potentially better treatment responses seen among Black men. If this could be better understood, perhaps it could be leveraged to further improve outcomes.”
Although Kishan and colleagues could not stipulate that radiotherapy has specific advantages for Black men with prostate cancer, their results suggest that, when under clinical trial care and receiving definitive therapy for localized disease, Black men have acceptable clinical outcomes, Bogdana Schmidt, MD, MPH, urologic surgeon at The University of Utah, and Neeraj Agarwal, MD, researcher in the department of internal medicine and the division of oncology at Huntsman Cancer Institute at The University of Utah, wrote in an accompanying editorial.
“Through a multidisciplinary effort of enriching cohort studies with Black men, enrolling Black men into clinical trials and continuing the search for tumor-specific genomic factors, treatment-specific response factors and pharmacologic response differences, as a community we can unequivocally improve prostate cancer care for Black men,” Schmidt and Agarwal wrote.
References:
Ma TM, et al. JAMA Netw Open. 2021;doi:10.1001/jamanetworkopen.2021.39769.
Schmidt B, et al. JAMA Netw Open. 2021;doi:10.1001/jamanetworkopen.2021.40692.
For more information:
Amar U. Kishan, MD, can be reached at University of California, Los Angeles, 200 Medical Plaza, Suite B265, Los Angeles, CA 90095; email:aukishan@mednet.ucla.edu.
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