After a diagnosis of breast cancer, Black women face a greater risk of having the disease spread to distant sites in the body—a disparity that is not readily explained, researchers say.
It’s known that in the United States, Black women have the highest death rates from breast cancer of any racial or ethnic group.
Compared with white women, Black women are 40% more likely to die of the disease, and twice as likely if they are older than 50, according to the American Cancer Society (ACS).
Those grim statistics are often blamed on the fact that Black women tend to be diagnosed at a later stage of the disease, said Dr. Julia Blanter, a resident at Mount Sinai’s Icahn School of Medicine, in New York City.
But in the new study, she and her colleagues found that later-stage diagnosis did not fully explain Black women’s risk of distant metastases. Those are tumors that spread far beyond the cancer’s original site, and they are the major cause of death among women with breast cancer.
Of 441 breast cancer patients in the study, most did not develop distant metastases during the follow-up period. But the percentage who did was substantially higher among Black women: roughly 7%, versus just over 1% of white women.
And even after the researchers accounted for stage at diagnosis, Black women were still almost six times more likely to develop distant tumors.
The question is, what is going on?
Blanter said it’s not clear what kind of treatment the study patients received, or which subtype of breast cancer they had.
And both of those factors could be at work, according to Dr. Farhad Islami, scientific director of cancer disparity research at the ACS.
“Overall, one of the major causes of racial and ethnic disparities in health outcomes is differences in access to care,” said Islami, who was not involved in the study.
He said obstacles in “access to and receipt of guideline-concordant treatment” likely contributed to Black women’s higher risk of distant metastases.
Beyond that, Islami said, it’s possible that Black women faced more difficulty sticking with treatment—for example, due to side effects and “inappropriate management” of those symptoms.
As for breast cancer subtypes, Islami noted that so-called “triple-negative” breast cancers are more common among Black women than their white counterparts. Those tumors are both more aggressive and have fewer treatment options than other, more common forms of breast cancer.
The findings are based on medical records from 441 women treated for breast cancer at Mount Sinai between 2013 and 2020. Over a typical follow-up of three years, 11 women developed distant metastases, including four white women and seven Black women.
That’s a small number of women, Islami pointed out, and the findings are considered preliminary: Blanter plans to present them at the American Society of Clinical Oncology’s annual meeting, which is being held online June 4 to 8, so they have not yet been published in a peer-reviewed journal.
“As such, results of this study should be interpreted with caution,” Islami said.
That caveat made, racial disparities in breast cancer are well-established, and there are ways to address them, according to Islami.
One way, he said, is through better insurance coverage to help more Black women receive “optimal” treatment. Communication between doctors and patients is also key, Islami added, so that women understand their treatment options, and plans can be made to help them stay with the treatment they ultimately choose.
Blanter agreed that the small number of women with distant metastases is a limitation of the study. At the same time, she said, the difference in risk between Black and white women was surprisingly large, and more research—including at other hospitals—is necessary.
“Once we understand more about what’s driving these disparities, we can start to do something about them,” Blanter said.