When can Axillary Lymph Node Dissection (ALND) be omitted in favor of Sentinel Lymph Node Biopsy (SLNB) in breast cancer patients?

When to Omit ALND in Favor of SLNB

ALND can be safely omitted in favor of SLNB alone in clinically node-negative early-stage breast cancer patients when the sentinel nodes are negative, and in specific scenarios where 1-2 sentinel nodes are positive if patients meet strict criteria for breast-conserving surgery with whole-breast radiation or mastectomy with regional nodal irradiation. 1

Patients with Negative Sentinel Lymph Nodes

Completion ALND should not be performed in patients with early-stage breast cancer who have negative sentinel lymph nodes. 1

• This recommendation is supported by 15-year follow-up data showing no statistically significant differences in event-free survival (72.8% vs 72.9%, P=0.953) or overall survival (82.0% vs 78.8%, P=0.502) between SLNB alone and ALND when sentinel nodes are negative 1, 2
• No axillary recurrences occurred in the SLNB-only arm at 14.3 years median follow-up, confirming long-term safety 2
• SLNB alone results in an 11.5% reduction in postsurgical complications compared to routine ALND 1

Patients with 1-2 Positive Sentinel Nodes: Breast-Conserving Surgery

ALND should be omitted in patients with clinically node-negative early-stage breast cancer (T1-T2, ≤5 cm) who have 1-2 positive sentinel nodes and will receive breast-conserving surgery with whole-breast radiotherapy. 1

This recommendation is based on:

• Patients must meet ACOSOG Z0011 trial eligibility criteria: clinical T1-T2, cN0 invasive breast cancer, 1-2 sentinel lymph nodes with metastases, no gross extracapsular extension, treated with breast-conserving surgery and tangential post-operative radiation including part of the axilla, plus adjuvant systemic therapy 1
• Long-term outcomes demonstrate equivalent survival without completion ALND in this population 1

Patients with 1-2 Positive Sentinel Nodes: Mastectomy

For patients undergoing mastectomy with 1-2 positive sentinel nodes, post-mastectomy radiation with regional nodal irradiation (RNI) may be offered in place of completion ALND. 1

Key considerations:

• This applies to clinically node-negative invasive breast cancer ≤5 cm 1
• The AMAROS trial demonstrated 10-year axillary recurrence rates of 0.93% with ALND versus 1.82% with axillary radiation therapy (HR 1.71,95% CI 0.67-4.39), with no differences in overall survival (HR 1.17,95% CI 0.89-1.52) or disease-free survival (HR 1.19,95% CI 0.97-1.46) 1
• Critical advantage: significantly lower lymphedema rates with radiation compared to ALND 1
• Decisions regarding RNI addition should consider the number of involved sentinel nodes and size of metastasis, with RNI reserved for macrometastases versus micrometastases 1

When ALND Remains Mandatory

ALND followed by RNI radiation therapy should be recommended in patients who receive mastectomy and have ≥3 positive sentinel nodes. 1

Additional scenarios requiring ALND:

• Patients with clinically suspicious or palpable axillary nodes after sentinel node removal 1
• Failed or technically unsatisfactory SLNB procedure 1
• Inflammatory breast cancer or N2/N3 stage disease (unless defined otherwise in clinical trial) 1

Special Populations Where SLNB Can Be Offered

SLNB may be performed in select special circumstances 1:

• Clinically node-negative patients with cT3-T4c tumors 1
• Multicentric tumors (clinically node-negative) 1
• DCIS treated with mastectomy 1
• Patients who are obese, male, or pregnant 1
• Prior breast or axillary surgery 1

When SLNB Can Be Completely Omitted

SLNB should not be routinely recommended in highly select patients who are postmenopausal, ≥50 years of age, with negative preoperative axillary ultrasound, grade 1-2, small (≤2 cm), hormone receptor-positive, HER2-negative breast cancer who undergo breast-conserving therapy. 1

Critical Pitfalls to Avoid

• Do not perform ALND based solely on imaging findings of suspicious nodes - even in patients with suspicious imaging, SLNB is safe and feasible, with imaging carrying only 82.1% sensitivity and 45.9% specificity for determining actual axillary metastasis 3
• Do not default to ALND for micrometastases - isolated tumor cells or micrometastases in sentinel nodes may be managed with axillary/locoregional radiation as an alternative to ALND if no impact on adjuvant systemic treatment is anticipated 1
• Ensure experienced surgical team - SLNB should only be performed by surgeons with demonstrated low false-negative rates (<10%) and high successful mapping rates (>90%) 1