Omission of Sentinel Lymph Node Biopsy in Early Breast Cancer: A Critical Appraisal of the SOUND, INSEMA, and BOOG 2013-08 Trials with a Proposed Clinical Selection Algorithm

Axillary management has undergone a major evolution over the past decades, progressing from routine axillary lymph node dissection to sentinel lymph node biopsy and now potentially toward further surgical de-escalation. Recent randomized trials have examined whether SLNB itself may be safely omitted in carefully selected patients with clinically node-negative disease.

This article provides a critical appraisal of the three major randomized trials investigating SLNB omission:

• SOUND trial
• INSEMA trial
• BOOG 2013-08 trial

The review analyses the methodological design, endpoints, imaging-based patient selection, and oncologic outcomes of these studies. Particular attention is given to the role of axillary ultrasound, tumour biology, radiotherapy techniques, and the implications of nodal staging for adjuvant systemic therapy decisions.

Current evidence suggests that omission of sentinel lymph node biopsy may be oncologically safe in highly selected patients with:

• small tumours (cT1 ≤2 cm)
• hormone receptor–positive / HER2-negative biology
• negative axillary ultrasound
• planned breast-conserving surgery and whole-breast radiotherapy

However, the available evidence remains limited for several clinically important subgroups, including HER2-positive disease, triple-negative breast cancer, invasive lobular carcinoma, and cT2 tumours.

The article also proposes a pragmatic clinical decision-making algorithm to assist multidisciplinary teams in selecting patients who may be candidates for SLNB omission while maintaining oncologic safety.

These findings contribute to the ongoing discussion on surgical de-escalation in breast cancer and highlight the importance of careful patient selection, high-quality imaging, and multidisciplinary decision-making.