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.

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 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.