Lymph Node Ratio as a Good Prognostic Factor for Patients with Pathologic N3a Breast Cancer with 10 or More Metastatic Axillary Lymph Nodes

Purpose: Pathologic N3a breast cancer is defined as having 10 or more metastatic axillary lymph nodes and metastases to the infraclavicular (level III axillary lymph) node. This study aimed to determine clinicopathological factors and assess the importance of lymph node ratio (LNR) as a prognostic factor for patient with N3a breast cancer treated with surgery without neoadjuvant chemotherapy.Methods: Medical records of 154 patients who underwent surgery were retrospectively analyzed. Patients were pathologically diagnosed with N3a breast cancer between May 2004 and December 2014. LNR was defined as the number of metastatic lymph nodes divided by the total number of resected lymph nodes. It was calculated using the receiver operating characteristic (ROC) curve. The median follow up period was 94 months (range, 10–205 months).Results: Among 154 patients with N3a breast cancer, 70 (45.5%) had recurrence and 40 (26.0%) died during the follow-up period. The 5-year disease free survival (DFS) and overall survival (OS) rates after surgery were 63.0% and 85.9%, respectively. LNR>0.82 (hazard ratio [HR]: 2.271; 95% confidence interval [CI]: 1.413–3.649; p=0.001) was a prognostic factor significantly associated with DFS. LNR>0.68 (HR: 2.156; 95% CI: 1.146–4.044; p=0.017) and invasive ductal carcinoma (HR: 0.125; 95% CI: 0.017–0.915: p=0.041) were significantly associated with OS.Conclusion: Although LNR values associated with DFS and OS are slightly different, LNR is a good prognostic factor for patients with N3a breast cancer.