A study published recently in JAMA Network Open underscored the importance of utilizing genetic ancestry beyond self-reported race in prognosticating breast cancer outcomes for Black women and addressing their disproportionately higher mortality rate.
The investigators found that West African genetic ancestry was associated with shorter disease-free survival, particularly for women with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR-positive/ERBB2-negative) breast cancer.
Among study participants with HR-positive/ERBB2-negative breast cancer, most of their tumors were classified as aggressive luminal B and basal subtypes, which are associated with shorter breast cancer disease-free survival (compared to luminal A tumors, which generally have a better prognosis). The investigators also observed that full-time employment was associated with improved outcomes, highlighting the importance of accounting for social determinants of health.
“This is among the first efforts to show that West African ancestry may contribute to poorer outcomes from breast cancer among Black women, recognizing that social drivers of health remain tremendously important,” said the study’s senior author, Tuya Pal, MD, Ingram Professor of Cancer Research and associate director for Cancer Health Disparities at Vanderbilt-Ingram Cancer Center.
“Our results highlight the importance of genetic ancestry beyond self-reported race, taking into account social drivers of health,” said the study’s lead author, Sonya Reid, MD, MPH, assistant professor of Medicine.
Although having a higher percentage of West African genetic ancestry was associated with shorter disease-free survival, that finding was not observed with the triple-negative breast cancer subgroup. While this finding might suggest that West African ancestry may be differentially associated with survival outcomes based on specific breast cancer subtypes, there were fewer women with triple-negative breast cancer limiting power to detect survival differences.
Black women continue to have a 40% higher mortality rate than white women despite improvements in breast cancer survival rates. They are also likely to be diagnosed at younger ages than white women.
“Our results highlight the importance of genetic ancestry beyond self-reported race, taking into account social drivers of health,” said the study’s lead author, Sonya Reid, MD, MPH, assistant professor of Medicine.
The study looked at 687 women with a median age at diagnosis of 44 years. Of this number, the researchers were able to assess global genetic ancestry for 551 of the participants. About 84% reported being born in the United States, while the remaining participants reported being born in Europe, the Caribbean, Africa and Latin America.
Other authors of the study from Vanderbilt University Medical Center include Run Fan, PhD, Lindsay Venton, BSc, Ann Weidner, MPH, Jibril Hibro, PhD, Jennifer Whisenant, PhD, Jennifer Pietenpol, PhD, Brian Lehmann, PhD, and Fei Ye, PhD.
The researchers received support from the National Cancer Institute (grants R01CA204819, P3OCAO68485, P5OCAO98131) and Susan G. Komen.
