Black:white disparities in breast cancer mortality in the 50 largest cities in the United States, 2005-2014.

Introduction: This paper presents race-specific breast cancer mortality rates and the corresponding rate ratios for the 50 largest U.S. cities for each of the 5-year intervals between 2005 and 2014.

Methods: The 50 largest cities in the U.S. were the units of analysis. Numerator data were abstracted from national death files where the cause was malignant neoplasm of the breast (ICD-10=C50) for women. Population-based denominators were obtained from the U.S. Census Bureau for 2010-2014. To measure the racial disparity, we calculated Black:White rate ratios (RRs) and confidence intervals for each 5-year period. To determine whether changes over time in the disparity were statistically significant, we calculated a 2-sided z score for the change in the relative percent difference between the Black and White rates for 2005-2009 and 2010-2014.

Results: At the most recent time point (2010-2014), the RR was significantly greater than 1.00 in the US and 24 cities. The change in the Black:White disparity was statistically significant in five cities and the US. The percent difference increased significantly in Atlanta, GA (from 4.1 to 117.4, p<0.001); San Antonio, TX (from 24.4 to 79.3, p=0.034); and the US (from 39.7 to 43.1, p=0.007). The percent difference decreased significantly in Memphis, TN (from 111.0 to 68.9, p=0.043); Philadelphia, PA (from 43.1 to 23.5, p=0.049); and Boston, MA (from 48.9 to 0.7, p=0.022).

Conclusion: This analysis provides updated city-level breast cancer mortality data for Black and White women through 2014, and reveals that in the US and 24 of the 43 largest US cities, Black women continue to die from breast cancer at a higher rate than their White counterparts. Importantly, however, a few cities, Memphis, Boston and Philadelphia, showed a decrease in the Black:White breast cancer mortality disparity between 2005-2009 and 2010-2014.