Role of surgery in patients with synchronous metastatic breast cancer: Is there a need for axillary lymph node removal?

Introduction: About 6% of women with breast cancer present with synchronous metastases. Treatment remains palliative in international recommendations but the impact of loco-regional surgery remains controversial. Objective: We conducted a multicentre, cohort study to evaluate the impact of axillary lymph node (ALN) surgery on overall survival in stage IV breast cancer at diagnosis. Methods: Patients presenting with breast cancer and synchronous metastases between 2005 and 2014 were included. Follow up was conducted up to 1st June 2018. The only exclusion criterion was a history of previous malignancies. Breast surgery was defined as lumpectomy or mastectomy. Axillary surgery included full ALN dissection, and sentinel lymph node biopsy (SLNB). If the SLN was invaded on the frozen section, full axillary dissection was performed. Results: 152 patients were included. 71 women had no surgery, 81 had primary site surgery of which 64 (79%) had breast and axillary surgery and 17 (21%) breast surgery only. 5-year overall survival was 59.8% (95% CI=[49.5; 69.5]) for women with breast and axillary surgery, 23.5% (95% CI=[15.6; 33]) for women with breast surgery only and 9.8% (95% CI=[4.7; 17.5]) for women without any surgery, p < 0.001. Combined with breast surgery, axillary surgery significantly added a mean of 33 months to patient overall survival. Conclusion: ALN surgery combined with breast surgery in metastatic breast cancer significantly increased overall survival. Thus surgical indications should not differ from those in women with breast cancer without metastases. (C) 2020 Elsevier Masson SAS. All rights reserved.