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Original Investigation
January 21, 2021

Association of Race/Ethnicity and the 21-Gene Recurrence Score With Breast Cancer–Specific Mortality Among US Women

Author Affiliations
  • 1Division of Hematology and Oncology, University of Illinois at Chicago, Chicago
  • 2Translational Oncology Program, University of Illinois Cancer Center, Chicago
  • 3Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, Massachusetts
  • 4Center for Pharmacoepidemiology Research, University of Illinois at Chicago, Chicago
  • 5Cancer Prevention and Control Program, University of Illinois Cancer Center, Chicago
  • 6Flatiron Health, New York, New York
JAMA Oncol. 2021;7(3):370-378. doi:10.1001/jamaoncol.2020.7320
Key Points

Question  Does breast cancer–specific mortality among US women with estrogen receptor–positive, axillary node–negative breast cancer differ by race/ethnicity within risk categories defined by the 21-gene Oncotype DX Breast Recurrence Score test, and does the prognostic accuracy of the recurrence score differ by race/ethnicity?

Findings  Using the Surveillance, Epidemiology, and End Results Oncotype database, this retrospective cohort study found that compared with non-Hispanic White women, Black women were more likely to have a high-risk recurrence score and had higher breast cancer–specific mortality within each risk category. The recurrence score also provided less prognostic information for Black women.

Meaning  The recurrence score should be calibrated in populations with greater racial/ethnic diversity.

Abstract

Importance  Given the widespread use of the 21-gene recurrence score for identifying candidates for adjuvant chemotherapy, it is important to examine the performance of the Oncotype DX Breast Recurrence Score test in diverse patient populations to validate this approach for tailoring treatment in women in racial/ethnic minority groups.

Objective  To examine whether breast cancer–specific mortality for women with hormone-dependent breast cancer differs by race/ethnicity across risk categories defined by the Oncotype DX Breast Recurrence Score test and whether the prognostic accuracy of the 21-gene recurrence score differs by race/ethnicity.

Design, Setting, and Participants  This retrospective, population-based cohort study used the Surveillance, Epidemiology, and End Results Oncotype DX 2004-2015 database to obtain breast cancer–specific survival data on US women 18 years and older who were diagnosed with first primary stage I to III, estrogen receptor–positive breast cancer between January 1, 2004, and December 31, 2015, and had tumor testing through the Genomic Health Clinical Laboratory. Data were analyzed from April 20 to September 27, 2020.

Main Outcomes and Measures  The primary outcome was breast cancer–specific mortality among women from different racial/ethnic groups stratified by the 21-gene recurrence score risk categories. Secondary analyses compared the prognostic accuracy of the recurrence score among the different racial/ethnic groups.

Results  A total of 86 033 patients with breast cancer (mean [SD] age, 57.6 [10.6] years) with Oncotype DX Breast Recurrence Score test information were available for the analysis, including 64 069 non-Hispanic White women (74.4%), 6719 non-Hispanic Black women (7.8%), 7944 Hispanic women (9.2%), 6950 Asian/Pacific Islander women (8.0%), and 351 American Indian/Alaska Native women (0.4%). Black women were significantly more likely than non-Hispanic White women to have a recurrence score greater than 25 (17.7% vs 13.7%; P < .001). Among women with axillary node–negative tumors, competing risk models adjusted for age, tumor characteristics, and treatment found higher breast cancer–specific mortality for Black compared with non-Hispanic White women within each recurrence score risk stratum, with subdistribution hazard ratios of 2.54 (95% CI, 1.44-4.50) for Black women with recurrence scores of 0 to 10, 1.64 (95% CI, 1.23-2.18) for Black women with recurrence scores of 11 to 25, and 1.48 (95% CI, 1.10-1.98) for Black women with scores greater than 25. The prognostic accuracy of the recurrence score was significantly lower for Black women, with a C index of 0.656 (95% CI, 0.592-0.720) compared with 0.700 (95% CI, 0.677-0.722) (P = .002) for non-Hispanic Whites.

Conclusions and Relevance  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. 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.

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    1 Comment for this article
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    Yes, race/ethnicity IS IMPORTANT
    Alexandre Mello de Azevedo, MD, MSc | Private practice
    A few days ago, JAMA published a study questioning the need for "race/ethnicity" to be part of the identification section in a patient's chart. The paper argued that race/ethnicity was "biologically irrelevant" and should not be annotated in the beginning of the patient's chart. Informing the patient's race/ethnicity, according to the authors of the study, was a result of "systemic racism in Medicine". I hope this new paper serves to enlighten the readers and editors about the biological importance of race/ethnicity, which remains strong even after a 21-gene panel has been done. We need less political activism and more objectivity. Leave this kind of discussion to Sociology journals.
    CONFLICT OF INTEREST: None Reported
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