Adherence Disparities and Utilization Trends of Oncotype Dx Assay: A National Cancer Database Study

Oncotype Dx (ODX) is a genetic assay that analyzes tumor recurrence risk and provides chemotherapy recommendations for T1-T2 stage, hormone receptor-positive, human epidermal growth factor receptor-negative, and nodal-negative breast cancer patients. Despite its established validity, the utilization of this assay is suboptimal. The study aims to evaluate factors that are associated with adherence rate with the testing guidelines and examine changes in utilization trends.

This is a retrospective study, utilizing data from the National Cancer Database from 2010 to 2017. Patients who met the ODX testing guidelines were first evaluated for testing adherence. Secondly, all patients who underwent ODX testing were assessed to evaluate the trend in ODX utilization.

A total of 429,648 patients met the criteria for ODX, and 43.4% of this population underwent testing. Advanced age, racial minorities, low-income status, well-differentiated tumor grade, uninsured status, and treatment at community cancer centers were associated with a decreased likelihood of receiving ODX in eligible patients. Additionally, a notable amount of testing was performed on patients who did not meet the ODX testing criteria. Among the 295,326 patients that underwent ODX testing, 16.6% of patients were node-positive and 1.8% had T3 or T4 stage tumors.

A considerable number of patients who were eligible for ODX did not receive it, indicating potential barriers to care and disparities in breast cancer treatment. ODX usage has been expanded to broader patient populations, indicating more research is needed to validate the effectiveness of the assay in these patient groups.