Black women with a common type of breast cancer are more likely to have aggressive tumors than white women, according to a recent study published in the journal npj Breast Cancer. This difference in tumor type, rather than race alone, helps explain why survival rates can differ between the two groups.
The study looked at women with a type of breast cancer called HR+HER2- early-stage breast cancer. Researchers used special DNA tests called MammaPrint and BluePrint to sort tumors into different groups based on how dangerous they were.
Black women were more than twice as likely to have the most aggressive tumor type, called Basal-Type, compared to white women (11% vs 4.8%). Fewer Black women had the safest, lowest-risk Luminal-A tumor type (37.2% compared to 54.7% in white women).
When women had the same tumor type, their survival rates were very similar regardless of race. Black women with the lowest-risk tumors had a 97.1% chance of being cancer-free after three years—nearly identical to white women with the same tumor type (95.9%). This suggests that tumor biology, not race itself, is the main driver of survival differences.
Because Black women were more likely to have aggressive tumors, they were more likely to receive chemotherapy (73.6% vs 47.1%). They were also more likely to have cancer that had spread to their lymph nodes (29.9% vs 17.5%), which makes treatment harder.
Read more about breast cancer types
The study authors said these findings show how important it is for all women to have access to genomic testing, which looks at the DNA of a tumor to understand how dangerous it is.
“These 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,” the authors wrote.
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