Supplementary Material for: Local Surgery Improves Survival in Patients with Primary Metastatic Breast Cancer: A Population-Based Study

The clinical value of local surgery in the breast cancer patients with distant metastasis is still unclear. A total of 8,922 primary metastatic breast cancer patients from the Surveillance, Epidemiology, and End Results (SEER) database were analyzed in the current study. Primary outcome variables included breast cancer-specific survival (BCSS) and overall survival (OS). Among the patients, 1,724 (19.3%) who underwent surgical treatment (ST) of primary breast tumor had increased OS (p p p p p p p = 0.886 for OS, p = 0.943 for BCSS). In conclusion,our study suggested that local surgery appeared to confer a survival benefit, which may provide new understanding of treatment for these patients.