Over the last 20 years, there has been a major problem in breast cancer prevention, as well as its diagnosis and care. That problem? While breast cancer mortality rates as a whole have improved by over 30 percent, a disproportionate number of black women continue to die from the disease as compared to their white counterparts. 

Understanding the gap

The latest study, released October 3, in the medical journal Cancer Epidemiology was funded by the Avon Foundation and a grant to Bijou Hunt at the Sinai Urban Health Institute. The study analyzed race-specific breast cancer mortality rates for the 50 most populous U.S. cities from 2010 to 2014. The study builds on our prior city-level analysis from 1990 to 2009.

The graphs showing city-level data illustrate an alarming trend in breast cancer mortality in black women compared to white women over the last 25 years. In 1990, black women were 17 percent more likely to die than white women, and only nine U.S. cities displayed statistically significant differences in black-white breast cancer mortality rates. By 2000, the disparity in breast cancer mortality in black women compared to white women increased to 35 percent on average, while 19 cities displayed statistically significant differences.

Data from the latest study shows further increase in the disparity in black-white breast cancer mortality — to 43 percent across the U.S. in the period of 2010 to 2014, with 24 cities displaying a statistically significant disparity. 

“...biology alone cannot explain the rapid growth of the disparity in 10 years and the geographic variation.”

Areas of concern

Focusing on what has occurred between the previous study period (2005-2009) and the most recent study period (2010-2014), the current study shows an alarming increase of the disparity in Atlanta, San Antonio and across the U.S. Importantly, Boston, Philadelphia and Memphis were three cities in which the disparity was significantly reduced between 2005-2009 and 2010-2014, but Boston was the only one of these three cities to achieve equality in black-white mortality rates by the most recent time period. Meanwhile, Philadelphia and Memphis continued to have significant yet improving disparities.

Racial disparities in breast cancer mortality are acknowledged at the national and state level. This study makes an important contribution by providing data at the city level, demonstrating geographic variation in the disparity and changes in the disparity over a 25-year time period.

Explaining gaps in risk

Together, these data suggest that differences in access to public health systems, and, hence, differences in access to and quality of mammography and treatment are likely contributing to the observed black-white disparities in breast cancer mortality. Earlier studies showed low median household incomes and a measure of segregation correlated with the disparity. Some cities have done better than others at addressing the disparity, such as New York and Minneapolis.

Access to care is not the only component that may be involved in the disparity. It has been well documented that the biology of the tumor can play a role in both incidence and outcome of breast cancer. For example, black women in the U.S. have been shown to be diagnosed with breast cancer at earlier ages, and a higher percentage are diagnosed with an aggressive form of the disease, called triple negative breast cancer. However, biology alone cannot explain the rapid growth of the disparity in 10 years and the geographic variation.

Having an impact

These studies were conducted to spur local city officials and health departments to take notice and take action to address the needs of their communities. Past reports resulted in citywide efforts to address the disparity in Chicago, Memphis, Boston, Houston and Washington D.C. Notably, Chicago, Memphis and Boston have all shown either a reduction in the disparity or an improvement in mortality rates among black women.

These findings underscore that where a patient may live should not determine if she lives — no matter her race.