Impact of HER2 receptor status on axillary nodal burden in patients with non-luminal A invasive ductal breast carcinoma.

Abstract

Breast cancer (BC) is the most common malignancy in women. To assess the impact of HER2 status on axillary lymph node (ALN) involvement in patients with invasive ductal carcinoma of no special type (IDC-NST) both at diagnosis and during the 4-year postoperative period. We retrospectively included 375 women with an early clinical stage of non-luminal IDC-NST who between 2007 and 2013 underwent breast surgery at a clinical hospital. They were divided into phenotype-based groups: HR+HER2-, HR+HER2+, HR-HER2+ and HR-HER2-. Only patients with sentinel lymph node (SLN) macrometastases underwent ALN dissection. If > 3 ALNs were positive, radiotherapy was delivered. All patients were treated with chemotherapy, HER2+ BC patients received trastuzumab, and hormone receptor (HR)-positive BC patients received hormonal therapy. Larger tumor size, higher grade, HR+, HER2+ status, and lymphovascular invasion (LVI) were predictive for ALN metastases at diagnosis. The poorest overall, disease-free, and distant recurrence-free survival (OS, DFS, DRFS) were found in the HR-HER2- group, while the poorest locoregional recurrence-free survival (LRFS) was observed in HR-HER2+ and HR-HER2- groups. HER2 status was not predictor of survival. HER2+ status was predictive for ALN involvement at diagnosis but had no effect on 4-year LRFS in these patients.