Advanced genetic testing could help erase significant disparities in breast cancer survival rates between white and Black patients, new research has found.
Currently, Black women in the U.S. have a 40% higher breast cancer mortality rate than white women, despite a 5% lower incidence of the disease.
Applying genetic testing to early breast cancer tumor samples collected from more than a thousand women, researchers found Black women had more high-risk tumors that are often missed by standard testing of clinical biomarkers, such as estrogen receptor status. That leads to under-treatment, which is likely to result in worse outcomes.
When tumors were analyzed by commercially available gene-profiling tools and patients had received appropriate care, Black women had the same “excellent” outcomes three years later as white women, according to a report of the study in npj Breast Cancer.
Tumor gene expression profiling was done using the MammaPrint and BluePrint tests from Agendia, which classify early-stage tumors as being at Ultra Low, Low, High 1, or High 2 risk for spreading throughout the body over the next 10 years. The results help to determine whether chemotherapy is necessary.
Three-year recurrence-free survival was driven by genomic subtype, not by race, the researchers found.
Black females with low-risk tumors based on MammaPrint and BluePrint had “excellent 10-year outcomes, with a 97.7% recurrence-free survival rate, the same outcome as white females,” the researchers reported.
Patients with high-risk tumors were five to 10 times more likely to develop distant metastases than those with low-risk tumors, regardless of race.
Roughly half of patients initially characterized as low-risk turned out to have more aggressive tumors based on genomic profiling, the researchers also found.
The data suggest “tumor genomic testing for all patients may help guide treatment decisions to ultimately reduce racial survival disparities among Black females with breast cancer,” said study coauthor Dr. Andrea Menicucci of Agendia.