Racial Disparities in HR+/HER2- Breast Cancer

By Leah Lawrence - Last Updated: December 20, 2022

Some Black women with hormone receptor (HR)-positive/HER2-negative breast cancer had worse outcomes compared with White women despite having similar genetic recurrence risk scores, according to data from the 2022 San Antonio Breast Cancer Symposium.

Yara Abdou, MD, assistant professor at the University of North Carolina at Chapel Hill and Lineberger Comprehensive Cancer Center, presented results of an analysis of clinical outcomes respective to race and ethnicity in women enrolled in the RxPONDER trial. The trial aimed to assess the value of the 21-gene recurrence score (RS) in patients with lymph-node positive, HR-positive/HER2-negative disease and the benefit of adjuvant chemotherapy in these patients.

Abdou and colleagues analyzed data from 4,048 women with 1-3 involved axillary lymph nodes. The women were predominantly non-Hispanic White (70%), followed by Hispanic patients (15.1%), Asian patients (8.0%), non-Hispanic Black patients (6.1%), and Native American/Pacific Islander (NAPI) patients 0.8%).

There was no difference in RS distribution between the racial subgroups. Additionally, there was no significant difference in tumor size or number of positive lymph nodes across racial subgroups. There were significantly greater grade 3 tumors among non-Hispanic Black patients (18.0%), NAPI patients (21.1%), and Hispanic patients (14.5%) compared with non-Hispanic White patients (10.4%) and Asian patients (6.5%).

The 5-year invasive disease-free survival rate was also lower for non-Hispanic Black patients (87.2%) compared with Asian patients (93.9%), non-Hispanic White patients (91.5%), and Hispanic patients (91.4%).

After adjusting for age, menopausal status, grade, treatment arm, and RS, non-Hispanic Black patients had a 37% percent higher risk of invasive cancer than non-Hispanic White patients. Additionally, non-Hispanic Black patients had lower distant relapse-free survival than non-Hispanic White patients.

These results do not seem to be associated with treatment compliance. At 12 months follow-up, 96% of non-Hispanic Black patients were still on endocrine therapy compared with 94.8% of non-Hispanic White patients.

“In accordance with previous studies, our results indicate racial disparities in breast cancer, particularly in HR-positive breast cancer. These differences were observed despite analyzing a carefully chosen and uniformly treated study population, suggesting that biological factors other than disparities in care may be contributing to inferior outcomes in racial minorities,” said Abdou. “Our findings also highlight the necessity for greater representation of racial and ethnic minorities in clinical trials.”

Abdou Y, Barlow, WE, Gralow JR, et al. Race and clinical outcomes in the RxPONDER trial (SWOG S1007). Abstract GS1-01. Presented at 2022 San Antonio Breast Cancer Symposium, San Antonio, Texas.