Contralateral axillary lymph node metastasis in breast cancer: An oligometastatic-like disease.

BACKGROUND: Contralateral axillary lymph node metastasis (CAM) is rare. It remains controversial whether CAM should be regarded as a regional or distant metastatic disease. Our study aims to investigate the accurate clinical orientation and management of CAM. METHODS: Two hundred and ninety-nine female patients diagnosed with breast cancer from 2000 to 2014 and confirmed to develop CAM, oligometastasis (OM) or locoregional recurrence (LRR) at Fudan University Shanghai Cancer Center (FUSCC) were included in this study. Baseline information and survival outcomes were analyzed and compared among the three groups. RESULTS: Patients with CAM exhibited similar overall survival (OS) and progression-free survival (PFS) to those with OM, but worse than those with LRR (HR: 0.47 [95 % CI: 0.27-0.85], p = 0.0097; HR:0.39 [95 % CI: 0.24-0.63], p < 0.0001, respectively). Considering the patients presented with CAM or OM as a whole, we found that local treatment combined with systemic treatment did not provide a superior survival benefit over systemic treatment alone. CONCLUSION: CAM was similar to an oligometastatic-like disease, and patients with these diseases may benefit from systemic treatment. Adding local treatment failed to significantly improve OS.