Chemotherapy use among women < 50 years with node-negative early-stage hormone receptor–positive breast cancer with intermediate OncotypeDX 21-gene recurrence score: A National Cancer Database analysis.

Abstract

e12546 Background: The Oncotype DX recurrence score (RS) multigene assay is widely-used to guide adjuvant chemotherapy (CT) decisions in early-stage hormone receptor–positive (HR+), HER2-negative breast cancer (BC). As RS does not explicitly account for the key prognostic factors of age or menopausal status, its use among premenopausal women < 50 years with intermediate scores (16–25) remains unclear. Specifically, while CT benefit may increase toward the upper end of this range, the magnitude of benefit has not been clearly defined. To this end, we sought to examine CT treatment patterns among women < 50 years with node-negative BC and intermediate RS utilizing National Cancer Database (NCDB). Methods: This retrospective NCDB analysis queried data from 2018-2022 for patients < 50 years (surrogate for premenopausal status) and clinically and pathologically node negative (pN0) stage I-III HR+ HER2-negative BC who underwent upfront surgery and had RS 16-25. Intermediate RS was further categorized using two subgroups: 16-20 and 21-25. Multivariable binary logistic regressions were used to examine the associations between clinical factors and receipt of CT stratified by each RS subgroup. Results: Data from 3,586 premenopausal women with pN0 and intermediate RS were analyzed: 2,382 patients had RS 16-20 and 1,204 had RS 21-25. A greater proportion of patients with RS 21-25 received CT compared to RS 16-20 (49.2% vs 10.6%, p < .001). Among those with RS 16-20, older age (aOR 0.92, 95% CI 0.89-0.94), higher pathologic tumor stage (aOR 6.33, 95% CI 2.90–13.82, pT3/4 vs pT1/2), higher grade disease [i.e. moderately (vs well) differentiated (aOR 1.89, 95% CI 1.34–2.67); poorly (vs well) differentiated vs (aOR 5.17, 95% CI 3.27–8.16)], and residing > 50 miles from the treatment facility (aOR 1.81, 95% CI 1.11-2.94) were associated with greater odds of CT receipt. While most of those factors were also associated with CT receipt among those with RS 21-25, distance from treatment facility did not retain significance for this cohort. Conclusions: Among women < 50 years with pN0 and intermediate RS, CT receipt was strongly associated with clinicopathologic factors for scores 16-20 and 21-25. These findings indicate that even in node-negative disease, clinicopathological factors continue to be accounted for in guiding CT decisions and are considered alongside RS when individualizing treatment in this population.