21-Gene Score in Ethnically Diverse, ER-Positive Breast Cancer: Implications for Young Non-Hispanic Black Women

By: Amanda E. Ruffino, BA
Posted: Wednesday, February 7, 2024

Hsiao-Ching Huang, MPH, PhD, of the University of Illinois College of Pharmacy, Chicago, and colleagues aimed to assess the clinical validity of the 21-gene breast recurrence score in predicting chemotherapy benefit among women from diverse racial and ethnic groups with estrogen receptor (ER)-positive, HER2-negative breast cancer. Previous research had indicated lower prognostic accuracy of the recurrence score for non-Hispanic Black women compared with non-Hispanic White women in the same category. Based on the findings published in JNCCN–Journal of the National Comprehensive Cancer Network, the recurrence score “was clinically validated as a predictive biomarker for non-Hispanic Black, Hispanic, and non-Hispanic White women with ER-positive, axillary node–negative breast cancer, but it may underestimate the benefit of chemotherapy for young non-Hispanic Black women,” the investigators stated.

The study authors turned to the Surveillance, Epidemiology, and End Results Program (SEER) Oncotype database; they focused on 6,033 Asian/Pacific Islander, 5,697 non-Hispanic Black, 6,688 Hispanic, and 54,945 non-Hispanic White women with stage I or II, axillary node–negative, invasive breast cancer.

The results revealed that chemotherapy significantly reduced breast cancer death for non-Hispanic Black (hazard ratio [HR] = 0.48), Hispanic (HR = 0.48), and non-Hispanic White (HR = 0.80) women, with a recurrence score of between 26 and 100. However, there was a nonsignificant reduction for Asian/Pacific Islander women (HR = 0.59) in the same recurrence score range. For women with a recurrence score between 11 and 25, there was no reduction in death for any racial of ethnic group. Of note, among women aged 50 or older, the reduction in breast cancer death with chemotherapy varied by race, with a significant interaction in young non-Hispanic Black women, who may benefit from chemotherapy at a lower recurrence score cutoff than other groups.

If these study findings are confirmed, the authors believe it might be necessary to lower the recurrence score cutoff for recommending adjuvant chemotherapy for young non-Hispanic Black women with ER-positive, axillary node-negative breast cancer.

Disclosure: For full disclosures of the study authors, visit jnccn.org.

JNCCN–Journal of the National Comprehensive Cancer Network