The impact of age and nodal status on variations in oncotype DX testing and adjuvant treatment.

Oncotype DX (ODX) recurrence score (RS) is a validated tool to guide the use of adjuvant chemotherapy (AC) in hormone receptor+/HER2- breast cancer. In this analysis, we examine (1) characteristics associated with ODX testing and (2) the association between ODX RS and receipt of AC across age and nodal status. Women with HR+/HER2-, early-stage (T1-2, N0-1) breast cancers from 2010-2017 in the National Cancer Database were included. 530,125 met inclusion and 255,971 received ODX testing. Older women were less likely to receive testing; however, nodal positivity increased use of testing. High ODX RS was associated with increased mortality, though the association was not consistent across age and was most strongly associated with mortality among younger, node-negative women. Older women with high ODX RS, regardless of nodal status, were less likely to receive AC. Clinicians may be employing ODX RS to support treatment decisions against the receipt of AC.