Prognostically Distinctive Subgroup in Pathologic N3 Breast Cancer

PURPOSE: The aim of this retrospective study was to investigate whether there are prognostically different subgroups among patients with pathologic N3 (pN3) breast cancer. METHODS: The records of 220 patients who underwent surgery for pN3 breast cancer from January 2006 to September 2012 were reviewed. All patients received adjuvant therapy according to standard protocols. The primary outcome was disease-free survival (DFS). RESULTS: Patients were followed for a median time of 68.3 months after their primary surgery (range, 10–122 months), during which time 75 patients (34.1%) had developed disease recurrence and 48 patients (21.8%) had died. The DFS and overall survival were 67.8% and 86.1%, respectively, at 5 years. Multiple logistic regression analysis showed that young age (<35 years, p=0.009), high serum neutrophil/lymphocyte ratio (>3.0) (p=0.020), high nodal ratio (number of metastatic lymph nodes divided by number of removed nodes) (>0.65) (p=0.062), and molecular phenotype (p=0.012) were significantly associated with tumor recurrence. Tumor biological subtype was the most significant predictor of recurrence. The 5-year DFS rates in patients with hormone receptor (HR) positive and human epidermal growth factor receptor 2 (HER2) negative, HR+HER2+, HR–HER2+, and triple negative subtypes were 82%, 63%, 58%, and 37%, respectively. CONCLUSION: Clinical outcomes of patients with extensive nodal metastasis were heterogeneous in terms of prognosis. Tumor biological subtype was the most important prognostic factor for pN3 disease. The prognosis of patients with HR+HER2– subtype in pN3 breast cancer was similar to that of patients with stage II breast cancer.