Inclusion Criteria:  Female patients aged ≥18 years with biopsy-proven invasive breast cancer Patients with cT1 or T2 tumors with palpable ipsilateral mobile adenopathy of level I/II axillary nodes with biopsy-proven nodal metastasis (cN1) who are undergoing BCS  Patients with tumors of the HR+/HER2- subtype, defined as:  HR+: Positive for estrogen receptor and/or progesterone receptor staining, indicated by ≥1% immunoreactive tumor nuclei HER2-: Immunohistochemistry assay demonstrating no or faint staining in ≤10% of tumor cells (IHC 0 or 1+) or negative by dual probe in situ hybridization assay  Exclusion Criteria:  Patients with occult primary breast cancer Patients with prior ipsilateral breast cancer Patients who are pregnant Patients with stage IV disease at presentation Patients with advanced regional disease (cN2/cN3)