Assessing the prognostic utility of Oncotype Dx among patients with ER-low-positive breast cancer in the National Cancer Database (NCDB)

Oncotype Dx (ODX) has not been evaluated in estrogen receptor (ER)-low-positive breast cancer (BC), a rare subtype with heterogeneous behavior. In this retrospective cohort of 2975 patients with ER-low-positive, node-negative BC eligible for ODX testing, a low/intermediate ODX recurrence score was associated with improved survival compared with a high ODX in multivariable models (hazard ratio = 0.57, 95% confidence interval = 0.33–0.98). These findings suggest that ODX is prognostic in ER-low-positive, node-negative, early-stage BC.