What recent trend has influenced axillary management in patients undergoing upfront surgery for early-stage breast cancer?

Recent Trend in Axillary Management for Early-Stage Breast Cancer

The most significant recent trend is the omission of sentinel lymph node biopsy (SLNB) altogether in carefully selected low-risk patients with small, clinically node-negative breast cancer and negative preoperative axillary ultrasound. 1

Evidence Supporting Complete Omission of Axillary Surgery

The 2025 ASCO guidelines now endorse omitting SLNB entirely based on two landmark randomized controlled trials—SOUND and INSEMA—which demonstrated non-inferiority of no axillary surgery compared to SLNB. 1

SOUND Trial Results

• 1,405 women with tumors ≤2 cm and negative preoperative axillary ultrasound were randomized to SLNB versus no axillary surgery 1
• 5-year distant disease-free survival was equivalent between groups with extremely low locoregional relapse rates (1.7% SLNB vs 1.6% no surgery) 1
• Only 13.1% had 1-3 positive nodes and 0.6% had ≥4 positive nodes when SLNB was performed, demonstrating minimal upstaging benefit 1

INSEMA Trial Results

• 4,858 patients with cN0, T1-T2 (≤5 cm) invasive breast cancer undergoing breast-conserving surgery were randomized 1
• 5-year invasive disease-free survival was 91.9% without axillary surgery versus 91.7% with SLNB (HR 0.91,95% CI 0.73-1.14), confirming non-inferiority 1, 2
• Significantly reduced morbidity in the no-surgery group: lymphedema (1.8% vs 5.7%), arm/shoulder mobility restriction (2.0% vs 3.5%), and pain (2.0% vs 4.2%) 1, 2

Specific Criteria for Omitting SLNB

Based on the populations well-represented in these trials, SLNB can be safely omitted in patients meeting ALL of the following criteria: 1, 3

• Age ≥50 years (younger patients were underrepresented: 18.6% in SOUND, 10.8% in INSEMA) 1
• Tumor size ≤2 cm (median 1.1 cm in SOUND; 90% had cT1 in INSEMA) 1
• Grade 1-2 disease (grade 3 represented only 18% in SOUND, 3.6% in INSEMA) 1, 3
• Hormone receptor-positive, HER2-negative (triple-negative only 5.4% in SOUND, 1.2% in INSEMA; HER2+ only 6.8% and 3.6% respectively) 1, 3
• Invasive ductal carcinoma (lobular/mixed lobular only 8.5-12.7% in trials) 1
• Negative preoperative axillary ultrasound (or single suspicious node negative by FNA) 1, 3
• Breast-conserving surgery planned 1, 3

Critical Caveat: Multidisciplinary Discussion Required

Adjuvant therapy decisions must be discussed BEFORE surgery when omitting SLNB, since nodal status will remain unknown and cannot guide systemic therapy escalation. 1, 3 This represents a fundamental shift from traditional staging-driven treatment algorithms.

Continued De-escalation for Positive Nodes

Beyond complete SLNB omission, the trend toward axillary de-escalation continues for patients with limited nodal disease: 1, 3

• ALND can be omitted in patients with 1-2 positive SLNs undergoing breast-conserving surgery with whole-breast radiation (Z0011 criteria remain standard) 1, 3
• Regional nodal irradiation serves as alternative to ALND for positive SLNs 3
• After neoadjuvant chemotherapy in initially node-positive patients converting to cN0, SLNB can replace ALND when using dual tracer, removing ≥3 nodes, and excising the clipped node 4, 2

Common Pitfall to Avoid

Do not perform intraoperative frozen section in mastectomy patients likely to receive postmastectomy radiation, as this leads to overtreatment with both ALND and radiation therapy in 41% of cases versus only 4.9% when intraoperative assessment is deferred. 5, 6 Waiting for final pathology allows appropriate selection of SLNB alone plus radiation versus ALND in the minority requiring completion dissection.