Black women have higher breast cancer recurrence and overall mortality compared with their white counterparts, even when they receive equivalent treatments, according to research presented at the 2018 San Antonio Breast Cancer Symposium (SABCS).
A team led by Dr. Kathy Albain from Loyola University Chicago found that even with equivalent treatments for breast cancer that is hormone receptor-positive and negative for human epidermal growth factor receptor 2 (HER2), black women have worse prognoses than women of other racial and ethnic backgrounds.
Albain's group assessed the association between clinical outcomes and race using data from the Trial Assigning Individualized Options for Treatment (TAILORx). The trial evaluated more than 10,000 women with the most common type of early breast cancer (that is, hormone receptor-positive, HER2-negative, and axillary lymph node-negative).
In the trial, researchers analyzed tumors for a recurrence score (scale of 0-100); women with a low risk score (0-10) were treated with hormone therapy alone, while those with a high risk score (≥ 26) were treated with hormone therapy and chemotherapy. Of the trial cohort, 84% were white, 7% were black, 4% were Asian, and 4% were of other or unknown race.
When Albain and colleagues analyzed the entire trial population, they found that black women had up to a 4% higher absolute risk of recurrence or death. When they compared outcomes between black and white women, they found that black women had a 39% higher relative risk of breast cancer recurrence and a 52% higher relative risk of death. Sixty-eight percent of black women in the trial had a recurrence score of 11 to 25.
The study results may point to biological differences among women of different races, Albain said in a statement released by the American Association for Cancer Research (AACR). The AACR is one of the hosts of the SABCS.
"The racial disparities observed in this trial were not explained by differences in recurrence score, duration, or reported adherence to hormone therapy, nor were they explained by use of chemotherapy, or characteristics such as age, tumor size, or tumor grade," she said. "As such, our results suggest that biological differences may contribute to the significantly different outcomes of black women compared to others with breast cancer."
