Race and Ethnicity May Affect 21-Gene Recurrence Score in Patients With Estrogen Receptor–Positive Breast Cancer

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Investigators have found that race and ethnicity may affect the 21-gene recurrence score in patients with early-stage, estrogen receptor–positive breast cancer, according to new findings presented by Gill et al at the 2023 ASCO Annual Meeting (Abstract 511).


The 21-gene recurrence score—ranging on a scale of 0 to 100—is a tool used to determine the risk of cancer recurrence and distant metastasis. Scores of 26 or higher indicate a greater risk of recurrence and poorer overall survival. Based on the expression of 21 cancer-related genes detected in pretreatment tumor specimens, recurrence scores are routinely used to identify patients who might benefit from chemotherapy.

“Increasing representation of racial and ethnic minorities is crucial to receiving detailed and specific results that indicate differences among populations,” explained lead study author Jasmin Gill, a second-year student at the University of Buffalo. “With increased representation, we can further our understanding of prognostic tests such as the 21-gene recurrence score, with implications for further study and treatment of cancers in racial [and] ethnic minorities,” she added.

Study Methods and Results

In the new observational cohort study, the investigators analyzed the data of 140,133 patients diagnosed with early-stage, estrogen receptor–positive breast cancer from 2006 to 2018 using from the National Cancer Database. All of the patients underwent surgery followed by adjuvant endocrine therapy, and had been assigned a 21-gene recurrence score.

The investigators then compared the recurrence scores and overall survival among 115,651 non-White Hispanic patients, 10,814 Hispanic patients, 5,455 Black patients, and 5,455 Asian/Pacific Islander patients. After a median follow-up of 66.2 months, the investigators found that compared with non-Hispanic White patients, Black patients were more likely to have a high recurrence score of ≥ 26 (P = .006)—although their overall survival rates were on par with that of patients in the other racial and ethnic groups who also had high recurrence scores. However, compared with non-Hispanic White patients, Black patients with a lower recurrence score of < 26 tended to have poorer overall survival rates than Hispanic or Asian/Pacific Islander patients who also had lower recurrence scores. Asian/Pacific Islander patients were found to have longer overall survival rates regardless of their recurrence scores.


The new findings contradicted the secondary analyses of two previous studies that found no relationship between recurrence scores and ethnicity. Both the TAILORx trial and RxPONDER trial evaluated the benefits of chemotherapy for patients with hormone receptor–positive breast cancer who had intermediate recurrence scores that fell between 11 and 25.

“African American [patients] were underrepresented in those national clinical trials, and secondary analyses showed they have 21-gene recurrence scores comparable to others,” noted co–study author Sung Jun Ma, MD, a resident in the Department of Radiation Medicine at the Roswell Park Comprehensive Cancer Center. “However, our study … suggested they were more likely to have more aggressive breast cancer—as indicated by having higher recurrence scores—and that among [patients] with high recurrence scores, there were no racial disparities in survival between African American and non-Hispanic White [patients],” he underscored.

“This study highlights the importance of considering the whole patient and their oncologic factors in decision-making,” stressed senior study author Anurag Singh, MD, Professor of Oncology and Director of Radiation Research in the Department of Radiation Medicine, Director of Head & Neck and Lymphoma Radiation Services, and Co-Leader of the Cancer Stress Biology Program at the Roswell Park Comprehensive Cancer Center as well as Professor of Medicine at the University of Buffalo Jacobs School of Medicine and Biomedical Sciences. “Our findings suggest that race should be reported and considered in the analysis of trials and large databases,” he concluded.

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