Redefining axillary management by selecting patients for omission of sentinel lymph node surgery in early breast cancer

Axillary staging has traditionally been performed routinely in early breast cancer to provide prognostic information and guide adjuvant therapy. In the era of targeted anti-tumor therapy and biology-driven treatment selection, however, the therapeutic relevance of nodal status has diminished in selected patients with clinically node-negative disease. Recent randomized trials, including Sentinel node vs. Observation after axillary UltraSouND (SOUND), INtergroup SEntinel MAmma trial (INSEMA), and Dutch Breast Cancer Research Group (BOrstkanker Onderzoek Groep; BOOG) 2013-08, have demonstrated that omission of sentinel lymph node biopsy (SLNB) in carefully selected patients undergoing breast-conserving surgery with planned whole-breast radiotherapy (WBRT) does not compromise local or distant disease control and rarely alters adjuvant systemic or radiotherapy management. The most robust evidence applies to postmenopausal women aged ≥ 50 years with ductal tumors ≤ 2 cm, grade 1–2, hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative and clinically node-negative disease. In this biologically favorable population, the therapeutic impact of nodal findings is limited as systemic therapy and radiotherapy decisions are predominantly driven by tumor subtype and genomic risk stratification rather than minimal nodal involvement. Based on evidence from recent randomized trials and current guidelines, this position paper proposes a practical four-step framework for decision-making regarding omission of SLNB. Redefining the axilla in this context represents a precision-oncology approach to surgical de-escalation, aligning local treatment intensity with biological risk while preserving oncologic safety.