Therapeutic role of axillary lymph node dissection in patients with stage IV breast cancer: a population-based analysis

Purpose To assess the clinical value of axillary lymph node (ALN) dissection in stage IV breast cancer. Methods Patients with a diagnosis of stage IV breast cancer from 1990 to 2010 were identified using the Surveillance, Epidemiology, and End Results database. Univariate and multivariate Cox regression analyses were performed to analyze the effect of ALN dissection and ALN status on breast cancer-specific survival (BCSS) and overall survival (OS). Results A total of 11,645 patients were identified. Of these, 7358 (63.2%) patients underwent ALN dissection, and 6168 (83.8%) patients showed nodal positivity. During this time, the rate of ALN dissection increased. Patients with delayed diagnosis, age <50 years, poorly/undifferentiated disease, larger tumor size (>2 cm), and married women were more likely to undergo ALN dissection. ALN dissection was associated with improved BCSS and OS in multivariate analysis. ALN dissection improved the survival in patients with bone and liver metastasis, and patients with single site of distant metastasis also had survival benefit by ALN dissection. Lymph node staging based on the number of positive lymph nodes was the independent prognostic factor for BCSS and OS in multivariate analysis; patients with advanced lymph node staging had a poor survival. Conclusions ALN dissection may improve survival in patients with stage IV breast cancer who received primary tumor surgery, especially in patients with bone, liver, and single site of distant metastasis. The lymph node staging was also the prognostic factor in patients with stage IV breast cancer.