Abstract

Should sentinel lymph node biopsy (SLNB) be omitted in carefully selected patients with clinically node-negative (cN0) early breast cancer? This question has become central in contemporary surgical oncology. For selected postmenopausal women with cT1, hormone receptor–positive/HER2-negative tumours undergoing breast-conserving therapy, recent phase III randomized trials suggest that omission of SLNB may provide outcomes comparable to standard axillary staging.
Axillary management has evolved from routine axillary lymph node dissection to selective SLNB. Recent randomized trials—including SOUND and INSEMA, with emerging phase III data from BOOG 2013-08—have evaluated the safety of omitting SLNB in patients with negative preoperative axillary ultrasound.
This review critically appraises these trials, focusing on their non-inferiority design, endpoint selection, imaging-based staging, biological selection, radiotherapy considerations, and implications for adjuvant therapy decisions. Despite differing primary endpoints, SOUND and INSEMA demonstrated statistical non-inferiority of SLNB omission in strictly selected populations, predominantly characterized by small HR+/HER2-negative tumours and negative axillary imaging.
However, premenopausal patients, HER2-positive and triple-negative subtypes, cT2 tumours, and invasive lobular carcinoma were underrepresented, and evidence for these groups remains limited. Based on available randomized evidence, key features supporting safe omission include postmenopausal status, cT1 tumour size (≤2 cm), HR+/HER2-negative biology, negative axillary ultrasound, planned breast-conserving surgery, and whole-breast irradiation.
SLNB omission should therefore be considered only for carefully selected patients within a multidisciplinary framework rather than adopted as routine practice. Longer follow-up and further subgroup validation remain necessary to confirm long-term safety.

Key words: Sentinel lymph node biopsy, Axillary staging, Early breast cancer, Surgical de-escalation, Non-inferiority trials, SOUND trial, INSEMA trial, Axillary ultrasound