Why is breast cancer often far more deadly for Black women than for White women?

October is Breast Cancer Awareness Month. It is recognized internationally to spread awareness of the disease and to allocate funds that will go towards researching the cause of the disease, prevention, diagnosis, treatment and cure.

According to the Centers for Disease Control and Prevention (CDC), although Black women have lower rates of getting breast cancer, Black women have higher rates of dying from the illness; breast cancer death rates are 40% higher for Black women. The CDC also published other alarming facts: breast cancer rates for Black women under 60 years of age are higher. White women also have a chance of earlier diagnosis as compared to black women. 

Black women are more likely to die from breast cancer than Whites largely due to racial disparities in healthcare, leading to delays in treatment or not getting the recommended treatment.

Indeed, statistics from CDC show that in the United States, about 255,000 women develop breast cancer each year, and approximately 42,000 women die. Breast cancer is the second leading cause of cancer death among women.

In 2018, demographic data showed that the rate of breast cancer occurrence between Black women and white women was similar. The rate of new breast cancer cases among Black women was 121.2 per 100,000 women while among white women, the rate was 127.5 per 100,000.

This wasn’t the case for the mortality rate. Per the data, white women had a breast cancer mortality rate of 19.2 per 100,000 cases while the mortality rate for Black women was 26.8 per 100,000 cases — 40% higher for Black women, as earlier stated.

“For early stage breast cancer, rates of survival are often greater than 90%, but among Women of Color, particularly African American women, we see much worse mortality rates, and that’s in part related to the fact that we have people presenting with later stage disease,” Dr. Lola Fayanju told BreastCancer.org.

Generally, breast cancer is often diagnosed later in Black women due to less access to healthcare services. But then researchers have also found that breast cancer tends to metastasize or spread more quickly in Black women.

Researchers recently studied 441 women with a diagnosis of breast cancer at Mount Sinai. They released their study on June 4 last year, reporting that of the small number of participants who developed metastases, about 7 percent were Black women compared with just over 1 percent of white women.

“We found that this disparity existed despite accounting for late stage diagnosis,” Dr. Julia Blanter, an internal medicine resident at the Icahn School of Medicine at Mount Sinai, told Healthline.

Cancer.org also attributes higher death rates from breast cancer among Black women to the:

1. Higher prevalence of obesity and other health issues

2. Higher incidence of triple-negative breast cancer, which is aggressive and challenging to treat. Black women are not only twice as likely to be diagnosed with triple-negative breast cancer than White women but are also 30% more likely to die from these tumors due to lower rates of surgery and chemotherapy.

3. Higher incidence of inflammatory breast cancer. This is not a common type of breast cancer but also aggressive.

Genetics

For Lisa Newman, a surgical oncologist, the genetics of breast cancer can also explain the differences between breast cancer in whites and Blacks. A 2017 study published in JAMA Oncology​ and cited by cancertoday shows that more than 40% of the variation in the frequency of breast cancer subtypes (such as triple-negative versus hormone receptor-positive breast cancer) between African Americans and whites is linked to ancestry.

Newman and others also conducted research that shows that women in Ghana in West Africa, which was once a center for the transatlantic slave trade, have a high frequency of triple-negative breast cancer. Cancertoday writes that “Almost all Ghanaian women carry a genetic variant known as the Duffy-null allele, a trait that is shared with African Americans who have western sub-Saharan African ancestry. The absence of Duffy antigens on blood cells is related to resistance to malaria, but it also plays a role in immune response.” Newman told the outlet that women from East Africa are less likely to have this variant and have lower incidence of triple-negative breast cancer.

“When it comes to cancer, we do also need to look at genetic ancestry, because genetics can impact tumor biology as well,” Newman added.