Kimberly Bertrand

Breast cancer is the most common cancer in women, but its burden weighs most heavily on the shoulders of Black women. With systemic racism and sexism having a profound impact on health, Black women are 40% more likely to die from breast cancer than White women. Efforts to reduce breast cancer risk and death have not closed the mortality gap between Black and White women.

What about being Black puts women at risk for a diagnosis of breast cancer? To answer this question, recent research is addressing the health impacts of the intersection between race and gender.

This is the mission of the Black Women’s Health Study (BWHS). Since 1995, the study has collected data on weight, nutrition, reproductive history, and lifestyle factors from a group of 59,000 Black women. Using these data, researchers are studying illnesses that disproportionately impact Black women, such as hypertension, diabetes, stroke, and breast cancer.

Kimberly Bertrand, an investigator with the BWHS, is working to understand the difference in the breast cancer death toll. Her current research focuses on the risk factors for mammographically dense breast tissue and aggressive breast cancers among Black women.

“Black women have traditionally been underrepresented in research,” says Bertrand. “While much progress has been made in understanding the causes of breast cancer and improving outcomes, clearly more work is needed.”

Bertrand spoke with Public Health Post about her work and some of the key findings from the BWHS.

Public Health Post: How did you become interested in cancer epidemiology?

Kimberly Bertrand: I was working in the Bureau of Environmental Health Assessment at the Massachusetts Department of Public Health after college. Part of my job was responding to resident concerns about potential “cancer clusters.” I spent time speaking to citizens about the risk of cancer in their neighborhoods and providing education about the causes and risk factors for cancer. I realized that there was still so much unknown about why some people get cancer and others don’t. I wanted to advance our knowledge about the causes of cancer, so I decided to pursue cancer epidemiology.

What important findings have come from the BWHS so far?

The BWHS has contributed foundational research on highly aggressive subtypes that occur twice as often in Black women compared to White women. Research shows that Black mothers who don’t breastfeed have an increased risk of estrogen-receptor negative breast cancer, shifting the previously held idea that giving birth decreases risk for all breast cancer subtypes.

The study also contributed to research on genes related to breast cancer. The gene mutations found in people with European ancestry are also relevant for women of African ancestry. Traditionally, Black women have been less likely to be referred to genetic testing for breast cancer compared to White women. These results show us that clinicians should also refer Black women for genetic testing.

Clinical models that predict women’s risk of breast cancer are developed based on data from a population of predominantly White women; these models can successfully predict breast cancer risk in White women, but not in Black women. Researchers in the BWHS developed and validated a new model to predict breast cancer in Black women. The new tool is available online and will be useful in identifying women at high risk for referral to screening or genetic testing before they reach the ages usually recommended for mammography. These studies were all piloted by Julie Palmer, co-founder of the BWHS.

How does being a Black woman affect access to breast cancer screening and treatment?

Due to historic and contemporary racist systems, Black women are more likely to live in disadvantaged or disinvested neighborhoods that lack high-quality, accredited mammography facilities than their White peers. The Affordable Care Act makes mammography screening free, but Black women may face additional barriers to screening, such as lack of transportation. Black women are also more likely than White women to be uninsured or underinsured and, therefore, face financial barriers to treatment.

These factors all contribute to delays in breast cancer diagnosis for Black women. Further, studies have shown that Black women are less likely than White women to receive and complete guideline-recommended treatment after their cancer diagnosis. These differences are likely driven by a combination of individual-, provider-, and system-level factors.

How can individual women, communities, and larger systems work to lower the risk of breast cancer in Black women?

While some known breast cancer risk factors, such as family history and reproductive factors, cannot be changed, there are some things women can do to reduce their risk. Women can maintain a healthy weight, be physically active, eat a healthy diet, and limit their alcohol consumption. Breastfeeding can also reduce their risk.

One of the most important things individual women can do is to get screened regularly. Early detection greatly improves the likelihood of treatment success. Addressing health disparities requires continued investment in both research and access to affordable high quality health care.