Breast cancer in Black women is a killer. Data published by the Breast Cancer Research Foundation in 2016 reveals that, in the 50 most populous U.S. cities, Black women are 43 percent more likely to die of breast cancer than white women, and that disparity is widening. Breast cancer is the most commonly diagnosed cancer in black women, according to the American Cancer Society, and is their second-biggest cancer-related killer, following lung cancer. But at the same time, Black women have a lower incidence rate of breast cancer than white women. What's going on?
This new dose of science about Black women and breast cancer comes courtesy of the Carolina Breast Cancer at the University of North Carolina, which has been studying breast cancer in women since 1993 and studied more than 8,000 women with the illness around the state. They've been attempting to figure out why black women have higher mortality rates for breast cancer for decades, and this latest study may provide a clue.
The Carolina scientists looked at 980 breast tumors in women, and subjected them to two kinds of tests, which would determine which types and subtypes the tumors belonged to. They then looked at the races and ages of the women who had these tumors, and found some distressing results. Young Black women, according to the researcher's numbers, are much more likely to have triple-negative breast cancers, which don't respond to many of the treatments we conventionally use for breast cancer. The "triple negative" name means that they don't have the three most common things we know fuel breast cancer growth and target in treatment: estrogen, progesterone, or HER2 gene. The National Breast Cancer Foundation explains:
"Since the tumor cells lack the necessary receptors, common treatments like hormone therapy and drugs that target estrogen, progesterone, and HER-2 are ineffective. Using chemotherapy to treat triple negative breast cancer is still an effective option."
But why do young Black women have a higher rate of a cancer that's got fewer treatment options and a higher mortality rate? There's one genetic explanation. A lot of triple-negative tumors, according to studies, seem to come from a genetic flaw: a faulty BRCA1 gene. (That's the faulty gene that, paired with her family history of deadly breast cancer, prompted Angelina Jolie to undergo a double mastectomy.) And a study published in 2015 in the journal Cancer found that young Black women seem to have a high likelihood of having this faulty gene.
That's not all the Carolina scientists found, though. Black women in their study were much less likely than white women to have luminal A breast cancer, which is the easiest to treat. They were 50 percent more likely than white women to have HER2-enriched breast cancer, and 45 percent more likely to have luminal B. And in subtypes which were hormone-receptor positive and HER2-negative (which can fall under either luminal A or B), black women's tumors were more aggressive and more likely to recur after treatment.
The researchers are using these results to argue that the genomic testing of tumors should be standard to help give doctors the most information about possible breast cancer treatment; but it's also an alarming bit of news that adds into generations of data that black women are more likely to die of breast cancer. And genetics seems to be part of the reason why.