Adjuvant Chemotherapy for Patients with Breast Cancer Based on Clinical and Evolving Oncotype DX Criteria

Introduction: Oncotype DX assay recurrence score (ODX-RS) cut-off values have recently changed after the publication of the TAILOR-X trial results. We aim to explore decisions for adjuvant chemotherapy (ACT) based on physicians' clinical assessment and the evolving ODX-RS. Methodology: Patients who underwent ODX testing after curative surgical resection of estrogen receptor positive (ER+), Her2 non-overexpressed (Her2-) and lymph node-negative (LN-) breast cancer (BC) were eligible. Management of these patients was guided by the results of the old ODX-RS-1 (<18, 18-30, and >= 31) risk grouping. For the purpose of this study, treatment decisions were also assumed according to TAILOR-X results (ODX-RS-2). Decisions of 3 medical oncologists on ACT were solicited by blinding them to the RS to investigate concordance with ODXA RS-1 and 2 recommendations. Results: Sixty-six consecutive patients were included. Median age was 50.5 (range: 21-73) years. There was 1 male patient, and 37/65 females (56.9%) were premenopausal. Among the 3 oncologists, recommendations for ACT based on clinical assessment were discrepant in 29 (43.9%) patients. Based on majority consensus (>= 2 oncologists), ACT would have been recommended to 22/41 (53.7%) and 22/46 (47.82%) patients with low-risk tumors according to ODX-RS-1 and ODX-RS-2, respectively. Compared to ODX-RS-1, ODX-RS-2 identifies 12% (46 vs. 41) more low-risk patients and 66% (20 vs. 12 patients) more high-risk patients. Conclusion: Overtreatment and discrepancies in the management of patients with ER+/Her2-/LN- early BC can be minimized by the implementation of ODX genomic assay. Some differences in ACT recommendations exist between ODX-RS-1 and ODX-RS-2.