Among patients with estrogen receptor (ER)-positive breast cancer, Black women are more likely to have a high-risk recurrence score, and those with axillary node–negative tumors have increased breast cancer–specific mortality within each risk category, according to a study now published in JAMA Oncology. In addition, the 21-gene Oncotype DX Breast Recurrence Score has less prognostic value for Black women.
"The most commonly ordered genomic assay for obtaining prognostic information on the risk of distant recurrence and for predicting the likelihood of benefit from adjuvant chemotherapy in women with estrogen receptor (ER)-positive breast cancer is the 21-gene recurrence score on the Oncotype DX Breast Recurrence Score test," write the investigators, led by first author Kent Hoskins, MD, Associate Professor in the Division of Hematology and Oncology at the University of Illinois College of Medicine. "Underrepresentation of women from racial/ethnic minority groups in the development and validation of the recurrence score raises questions about the prognostic accuracy of the Oncotype DX Breast Recurrence Score Test in populations other than non-Hispanic White people. This issue is especially relevant in light of persistent racial disparities in survival among black women with ER-positive breast cancer."
Using the Surveillance, Epidemiology, and End Results (SEER) Oncotype DX database, Dr. Hoskins and colleagues evaluated breast cancer-specific survival data for 86,033 women diagnosed with stage I–III, ER-positive breast cancer between 2004 and 2015. Non-Hispanic Black women comprised 7.8% of the study population. The primary end point was breast cancer-specific mortality among the different racial and ethnic groups, stratified by 21-gene recurrence score risk categories, with recurrence scores classified as low risk (scores between 1 and 10), intermediate risk (scores between 11 and 25), or high risk (scores greater than 25).
A higher proportion of Black patients had a recurrence score greater than 25 compared with non-Hispanic White patients (17.7% vs 13.7%). Among patients with axillary node-negative tumors, Black race was associated with a significantly higher breast-cancer specific mortality among all recurrence score risk groups, with hazard ratios of 2.54 for low risk, 1.64 for intermediate risk, and 1.48 for high risk. Among patients with node-positive disease, no racial disparities in mortality were observed. Age younger than 40 years, larger tumor size, higher American Joint Committee on Cancer (AJCC) stage and tumor grade, and progesterone receptor (PR)-negative tumor status were also associated with a high-risk recurrence score. The Oncotype DX Breast Recurrence Score test had substantially lower prognostic accuracy among black patients compared with non-Hispanic White patients (hazard ratios of 1.58 vs 1.71).
"In this cohort study, Black women in the US were more likely to have a high-risk recurrence score and to die of axillary node-negative breast cancer compared with non-Hispanic white women with comparable recurrence scores," conclude Dr. Hoskins and colleagues. "The Oncotype DX Breast Recurrence Score test has lower prognostic accuracy in Black women, suggesting that genomic assays used to identify candidates for adjuvant chemotherapy may require model calibration in populations with greater racial/ethnic diversity."
For More Information
Hoskins KF, Danciu OC, Ko NY, et al (2021). Association of race/ethnicity and the 21-gene recurrence score with breast cancer-specific mortality among US women. JAMA Oncol. [Epub ahead of print] DOI:10.1001/jamaoncol/2020.7320
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