Prognostic consistency of oncotype DX® molecular assay across racial groups in early-stage hormone receptor-positive breast cancer

In this retrospective cohort study, we evaluated the consistency of prognostic outcomes provided by the Oncotype DX® assay across different racial groups among women with early-stage hormone receptor-positive (HR + ) breast cancer. Data was abstracted from the electronic medical record of 1122 patients with non-metastatic HR+ breast cancer who underwent Oncotype DX testing at University Hospitals Seidman Cancer Center between 2013 and 2023. Recurrence Score (RS) categories were defined using historical cutpoints: low(0-18), intermediate(19-30), and high(31-100). Two contemporary-cutpoint sensitivity analyses based on TAILORx and RxPONDER were also performed: binary scheme (0-25;26-100) and three-level scheme (RS 0-15;16-25;26-100). Recurrence-free survival (RFS) and overall survival (OS) were analyzed using Kaplan-Meier curves and adjusted Cox models. The cohort included 142 African American (AA) and 967 White women. Under the historical cutpoints, AA women had a higher prevalence of intermediate and high-risk RS. Despite these differences, 5-year RFS and OS were comparable. In multivariable analyses, AA race was not independently associated with RFS or OS. Sensitivity analyses using contemporary cutpoints yielded concordant findings. These findings support consistent prognostic value of Oncotype DX assay across racial groups, although further investigation into socioeconomic and clinical contributors to disparities is warranted.