Although breast cancer continues to be the most common cancer diagnosed in women in the United States, and remains the second-leading cause of cancer death, over the past several decades, the disease has affected Black and White women differently. According to the findings of a large retrospective cohort study evaluating 26-year trends in survival by race/ethnicity for women with breast cancer, although breast cancer mortality rates have decreased more among Black and Hispanic women than White women since 1990, Black women still have double the 5- and 10-year mortality rates compared with White women. The study’s results highlight the need for targeted approaches to eliminating disparities in breast cancer survival for Black women, according to the study authors. The study by Hines et al was published in Cancer Epidemiology, Biomarkers & Prevention.

Study Methodology

The researchers obtained records from the Florida Cancer Data System of more than 257,000 women diagnosed with breast cancer from 1990 to 2015. Most women in the study were non-Hispanic White (79.5%), followed by Hispanic White (10.5%), non-Hispanic Black (9.7%), or Hispanic Black (0.3%). The cumulative incidence estimates of 5- and 10-year breast cancer–related death with 95% confidence intervals (CI) were obtained by race-ethnicity according to diagnosis year.

The Fine-Gray subdistribution hazard regression model was used to estimate subdistribution hazard ratios with 95% CI for the relative hazard rate of breast cancer death accounting for competing causes. The researchers clustered patients based on their year of diagnosis: 1990–1994, 1995–2004, and 2005–2015.

Results

The researchers found that breast cancer mortality decreased for all racial-ethnic groups and that racial-ethnic minorities had greater absolute and relative improvement for nearly all metrics compared with non-Hispanic White women. In non-Hispanic White women, the 10-year morality decreased from 20.6% from 1990 to 1994 to 14.0% in the final period of 2010 to 2015. In non-Hispanic Black women, the 10-year mortality decreased from 36.0% to 25.9%.

In the most recent 10 years examined, there was no significant difference in 5- or 10-year mortality rates between Hispanic White and non-Hispanic White women. When the researchers normalized the mortality data based on age, insurance status, census-tract poverty, tumor stage and grade at diagnosis, and treatment received, the 10-year relative rate of breast cancer mortality for Black women decreased to 20% higher than White women.

“Despite efforts to improve disparities in breast cancer outcomes for underserved women in Florida, Black women continue to experience significant survival disparities,” concluded the study authors.

Ensuring Equitable Outcomes for Black Women With Breast Cancer

In a statement commenting on the study’s results, lead author Robert B. Hines, PhD, MPH, Associate Professor of Population Health Sciences at the University of Central Florida College of Medicine, said: “Over the past 3 decades, we’ve seen an improvement in breast cancer survival for all women, especially for minority women, which is encouraging. However, in the most recent time period, non-Hispanic Black women have twice the rate of breast cancer death compared to non-Hispanic White women. We need to celebrate the progress we make, but we have a way to go to produce equitable outcomes for women diagnosed with breast cancer.”

Disclosure: Funding for this study was provided by the University of Central Florida College of Medicine. The study authors reported no conflicts of interest.