Is Axillary Sentinel Lymph Node Biopsy Required in Patients Who Undergo Primary Breast Surgery?

Local treatment of the axilla in clinically node-negative (cN0) early breast cancer patients with routine sentinel lymph node biopsy (SLNB) is debated for various reasons: i) pN staging information may not be necessary for the postoperative treatment decision regarding adjuvant systemic therapy in the great majority of patients; ii) the SLNB-positive rate is declining below 20% in specialized breast centers; iii) albeit being a minimally invasive procedure, SLNB causes a significant reduction in quality of life in 23% of patients; and iv) previous randomized trials from the pre-SLNB era did not show a disadvantage for patients without axillary surgery with regard to overall survival. These data support the hypothesis that avoiding axillary treatment in patients with clinically and sonographically unsuspicious lymph nodes seems to be a safe option, although omitting axillary surgery may increase the risk of locoregional recurrence. Currently, the information regarding node-positive status is essential to guide postoperative treatment such as systemic or radiation therapies in a non-negligible minority of patients. Three ongoing prospective European trials (SOUND, INSEMA, BOOG 2013-08) with axillary observation alone versus SLNB in cN0 patients and primary breast-conserving surgery have the objective to evaluate oncologic safety when omitting SLNB.