Although the gap in breast cancer mortality rates between Black and white women has narrowed over the last three decades, disparities are still prevalent, according to research published July 1 in Cancer Epidemiology, Biomarkers & Prevention.
Researchers led by Robert Hines, PhD, from the University of Central Florida found that cancer-specific mortality rates in Florida have decreased more among Black and Hispanic women than white women since 1990.
However, Black women still have double the five- and 10-year mortality rates of non-Hispanic white women.
"We were encouraged that breast cancer survival in minority women improved to a greater degree over time when compared with rates for non-Hispanic white women," Hines told AuntMinnie.com. "Unfortunately, Black women continue to experience significantly worse survival, with non-Hispanic Black women having the largest disparity."
Breast cancer ranks first in incidence and second in mortality to lung cancer among women in the U.S. However, trends over time vary by race and ethnicity, with Black women dying from breast cancer at a higher rate than white women.
While advances in medical technology and emphasis on breast cancer screening have helped decrease mortality rates since 1990, disparities have been prevalent in the proportion of women who were up to date with screening mammography according to race and ethnicity.
Hines and his colleagues wanted to see just how much the gap has narrowed and collected data for over 257,171 Florida women diagnosed with breast cancer from 1990 to 2015.
Out of those, 79.5% identified as non-Hispanic white, 10.5% non-Hispanic Black, 9.7% Hispanic white, and 0.3% Hispanic Black.
The researchers studied the cumulative incidence of breast cancer death as well as 5- and 10-year relative hazard rates for individuals in each group. They clustered patients together based on year of diagnosis: 1990-1994, 1995-1999, 2000-2004, 2005-2009, and 2010-2015.
They found that mortality declined for all racial-ethnic groups and that minority groups had greater absolute and relative improvement for nearly all metrics compared with non-Hispanic white women.
| Overall breast cancer mortality rate changes by race/ethnicity | ||||
| 5-year | 10-year | |||
| Absolute difference | Percent decrease | Absolute difference | Percent decrease | |
| Non-Hispanic white | -2.2% | 15.7% | -6.6% | 32.04% |
| Non-Hispanic Black | -5.8% | 20.0% | -10.1% | 28.06% |
| Hispanic white | -3.6% | 21.2% | -8.7% | 35.51% |
| Hispanic Black | -5.5% | 19.8% | -8.6% | 23.50% |
But despite the gains, Black women still had much higher mortality rates for breast cancer. The percentage of women who died of breast cancer within five years in the time earliest study time period (1990-1994) was: 14% (non-Hispanic white), 29% (non-Hispanic Black), 17% (Hispanic white), and 27.8% (Hispanic Black).
When compared with survival in the most recent period (2010-2015), all women experienced better survival, with greater gains in minority women: 11.8% (non-Hispanic white), 23.2% (non-Hispanic Black), 13.4% (Hispanic white), and 22.3% (Hispanic Black).
The team also found that although women of Hispanic ethnicity had slightly poorer survival in the earlier years of the study (1990-2004), there was no survival disadvantage associated with Hispanic ethnicity for 2010-2015.
"This was a positive finding that we found somewhat surprising," Hines told AuntMinnie.com.
However, Black women still face significant survival disparities, the researchers wrote.
The group is analyzing recent cases in the study group to identify factors driving poorer survival outcomes among non-Hispanic Black women and evaluating regions of Florida with the highest racial disparities in survival outcomes.
The study authors wrote that the study's data will be used to inform policies, programs, and interventions in areas of the state in the greatest need of reducing inequalities.
Hines said that efforts at the clinic or health system level to remove barriers to high-quality breast cancer treatment for racial and ethnic minorities "would go a long way" toward reducing disparities in breast cancer survival.
