This focused update addresses the use of Onco DX in guiding decisions on the use of adjuvant systemic therapy.

ASCO uses a signals approach to facilitate guideline updating. For this focused update, the publication of the Trial Assigning Individualized Options for Treatment (TAILORx) evaluating noninferiority of endocrine therapy alone versus chemoendocrine therapy for invasive disease-free survival in women with Onco DX scores provided a signal. An expert panel reviewed the results of TAILORx along with other published literature on the Onco DX assay to assess for evidence of clinical utility.

For patients with hormone receptor-positive, axillary node-negative breast cancer whose tumors have Onco DX recurrence scores of less than 26, there is little to no benefit from chemotherapy, especially for patients older than age 50 years. Clinicians may recommend endocrine therapy alone for women older than age 50 years. For patients 50 years of age or younger with recurrence scores of 16 to 25, clinicians may offer chemoendocrine therapy. Patients with recurrence scores greater than 30 should be considered candidates for chemoendocrine therapy. Based on informal consensus, the panel recommends that oncologists may offer chemoendocrine therapy to these patients with recurrence scores of 26 to 30. Additional information can be found at www.asco.org/breast-cancer-guidelines.