New research published today in JNCCN‑Journal of the National Comprehensive Care Network adds more evidence to how the lack of genomic research for people of African Ancestry continues to negatively affect efforts to reduce disparities in cancer care for this group of patients. The researchers note that this is especially true for people whose ancestry traces to Sub-Saharan Africa.
Now, in what NCCN touted as a first-of-its-kind study, researchers led by Kazzem Gheybi, MD, PhD, of The University of Sydney in Australia, have generated new data on the genetic profiles of 113 black South African men to find unique markers of prostate cancer. Prostate cancer mortality rates among populations with significant African ancestry, such as the Caribbean and Sub-Saharan Africa, are significantly higher at 3.4-times and 2.5 times, respectively, than the rate reported in the U.S. Within the U.S., black men shown mortality rates from prostate cancer of between 2.3 to 5 times the rates of non-black men.
“Although men of African ancestry have the highest incidence rates for aggressive prostate cancer and associated death globally, due to lack of available data, no tailored testing criteria have been established for such populations at increased risk,” Gheybi. “This study opens the door to begin to establish new criteria, providing men of African ancestry with hope that germline testing can change current disparities in clinical outcomes.”
Senior author Vanessa M. Hayes, PhD, from The University of Sydney and the University of Pretoria in South Africa cautioned against interpreting the results of the new research in “singular” terms, pointing out that the African diaspora is highly diverse.
“What is required is concerted effort for inclusion that takes a grassroots approach. We need to build criteria based on population-specific knowledge. We encourage cancer care and germline screening providers to establish a research and development arm tailored specifically for African inclusion,” Haynes noted. “We need to move away from the one-size-fits-all model for prostate cancer care; African solutions should address African-relevant disparities in prostate cancer outcomes.”
For this study, the researchers examined 21,899 single-nucleotide variants, 4,626 small insertions and deletions, and 73 structural variants across 20 genes from the 113 patients in the study. After the researchers excluded those variants that were known not to be pathogenic, they identified 38 mutations across 52 patients. From those at total of four pathogenic and 13 potentially oncogenic variants were identified. This represented a 5.6% rate of identification of cancer-causing variants in this population, much lower than the rate of 11.8% for non-African patients with confirmed metastatic prostate cancer. This strongly suggests decreased sensitivity of currently available gene panels for risk assessment in this population.
Samuel L. Washington III, MD, MAS, Assistant Professor of Urology; Epidemiology & Biostatistics, University of California, San Francisco (UCSF) and a member of the the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) Panel for Prostate Cancer Early Detection said the study provides more evidence for the need to develop more inclusive development of genetic testing panels, while also acknowledging that care disparities can’t be solely by these recent findings.
“Although the NCCN Guidelines for Prostate Cancer Early Detection identify Black/African American identity as a risk factor, the panel notes the contributions of poor access to care, social determinants of health/social risk, and heritable genes to these observations,” added Washington, who was not involved in the recent study. “I look forward to further research in this area that examines how the limitations of our current tools can be improved to better reflect the populations we serve.”
