Senior author Kevin Kalinsky, MD, MS, of Winship Cancer Institute of Emory University, led a global clinical trial that found that non-Hispanic Black (Black) women with Hormone Receptor positive/HER2-negative breast cancer, with 1-3 involved lymph nodes and recurrence scores below 25, have worse outcomes than non-Hispanic white (white) women with a similar diagnosis.
The trial’s findings were reported at the 2022 San Antonio Breast Cancer Symposium on Dec. 6. The findings revealed that black women had lower overall five-year invasive disease-free survival (IDFS) compared with other racial and ethnic groups, and worse distant relapse-free survival (DRFS) than white women.
HR+/HER2- is the most common subtype of breast cancer. If diagnosed early, it is also one of the most survivable with a 100% five-year survival rate if the disease is detected and treated before it has metastasized and involves any other area of the body.
The phase 3 RxPONDER Trial (NCT01272037), conducted by the SWOG Cancer Research Network, a cancer clinical trials group funded by the National Cancer Institute, analyzed the clinical outcomes of 4,048 women with HR+/HER2- with respect to race and ethnicity. The women assessed included 2,833 white patients (70%), 248 Black patients (6.1%), 610 Hispanic patients (15.1%) and 324 Asian patients (8%). Black and white patients were the same ages.
Although there were no significant differences in tumor size, number of positive lymph nodes or the 21-gene recurrence scores across all racial/ethnic groups, Black and Hispanic women had significantly higher rates of grade 3 tumors than white and Asian women. Black women were more likely to accept and comply with treatment than white women, suggesting that their poorer outcomes are not the result of not complying with treatment.
Kalinsky, who collaborated on this study with first author Yara Abdou, MD, of the University of North Carolina, says that future studies will examine how tumor biology, gene groups, health care access and social factors, as well as treatment completion and adherence beyond the first year may contribute to outcome differences by race.