Clinical Outcomes in Breast Cancer Patients with HER2-Positive, Node-Negative Tumors (≤3 cm)

Abstract

Purpose The present study aimed to evaluate clinical outcomes in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) with node-negative tumors ≤ 3 cm who received adjuvant chemotherapy and HER2-targeted therapy. Methods The present study enrolled patients with HER2-positive BC who underwent breast and axillary surgery between January 2007 and August 2020. Patients receiving neoadjuvant chemotherapy were excluded. The endpoint was time to distant disease-free survival (D-DFS) as estimated using Kaplan-Meier curves. The secondary endpoints were disease-free survival (DFS) and overall-survival (OS). These outcomes were compared between patients with pT1a or pT1b tumors (the pT1a/b group), those with pT1c tumors (the pT1c group), and those with pT2 tumors (the pT2 group). Results In total, 135 patients were included. Among these, 28 (20.7%) had pT1a or pT1b tumors (the pT1a/b group), 67 (49.6%) had pT1c tumors (the pT1c group), and 40 (29.6%) had pT2 tumors (the pT2 group). After a median follow-up period of 5.4 years, the 5-year-D-DFS was 100%, 94.2%, and 97.1% in the T1a/b-, T1c-, and T2 group, respectively. The 5-year-DFS rate was 100%, 92.1%, and 93.3%, and the 5-year-OS rate was 100%, 94.9%, and 97.0%, in the respective groups. Conclusions Patients with HER2-positive, node-negative tumors ≤ 3 cm who received trastuzumab and chemotherapy had a favorable 5-year-D-DFS (96.3%). Among them, those with a tumor 1 cm or less in size had better outcomes.