Nodal positivity and systemic therapy among patients with clinical T1–T2N0 human epidermal growth factor receptor-positive breast cancer: Results from two international cohorts

Abstract

Background: The optimal treatment strategy for patients with small human epidermal growth factor receptor 2 (HER2)-positive tumors is based on nodal status. The authors’ objective was to evaluate pathologic nodal disease (pathologic lymph node-positive [pN-positive] and pathologic lymph node-positive after preoperative systemic therapy [ypN-positive]) rates in patients who had clinical T1–T2 (cT1–cT2)N0M0, HER2-positive breast cancer treated with upfront surgery or neoadjuvant chemotherapy (NAC). Methods: Two databases were queried for patients who had cT1–cT2N0M0, HER2-positive breast cancer: (1) the Dana-Farber Brigham Cancer Center (DF/BCC) from February 2015 to October 2020 and (2) the Hospital Clinic of Barcelona and the Hospital Clinico of Valencia (HCB/HCV) from January 2012 to September 2021. The pN-positive/ypN-positive and axillary lymph node dissection (ALND) rates were compared between patients who underwent upfront surgery versus those who received NAC. Results: Among 579 patients from the DF/BCC database, 368 underwent upfront surgery, and 211 received NAC; the rates of nodal positivity were 19.8% and 12.8%, respectively (p =.021). The pN-positive rates increased by tumor size (p