What are the current approaches to axillary management in breast cancer?

Changing Concepts in Axillary Management of Breast Cancer

Current Standard of Care

Sentinel lymph node biopsy (SLNB) has replaced axillary lymph node dissection (ALND) as the standard approach for axillary staging in clinically node-negative early-stage breast cancer, providing equivalent staging accuracy while dramatically reducing morbidity including lymphedema, pain, and sensory loss. 1

Algorithmic Approach to Axillary Management

For Clinically Node-Negative Patients (cN0)

Primary staging approach:

• SLNB is the procedure of choice for patients with clinical Stage I or II breast cancer and clinically negative axillary nodes confirmed by physical examination or negative core/FNA biopsy 1, 2
• The procedure requires an experienced sentinel lymph node team with identification rates ≥90% and false-negative rates ≤10% 2
• Surgeons should perform 20-30 sentinel node biopsies with concurrent ALND during their learning phase to establish technical accuracy 2

When SLNB is negative:

• No further axillary surgery is required 1
• Patients proceed with appropriate breast surgery and systemic therapy based on tumor characteristics 1

When SLNB shows micrometastases (0.2-2.0 mm):

• No completion ALND is required in treatment-naïve patients, as micrometastases are prognostically equivalent to N0 disease 1
• This represents a major shift from historical practice

When SLNB shows macrometastases:

• For patients with T1/T2 tumors, ≤2 positive sentinel nodes, undergoing breast-conserving surgery with whole breast irradiation and systemic therapy: SLNB alone without completion ALND is recommended 1
• This is based on evidence showing no survival benefit from completion ALND in this specific population
• If >2 positive nodes or mastectomy without radiation, proceed with Level I and II ALND 2

For Patients Receiving Neoadjuvant Chemotherapy

Timing of SLNB:

• Pre-chemotherapy SLNB is the preferred approach for patients with clinically negative axillary nodes 2
• This provides additional information to guide local and systemic treatment decisions 2

If pre-chemotherapy SLNB not performed:

• Level I and II ALND (category 2A) or post-chemotherapy SLNB (category 3) should be performed at definitive surgery 2
• Post-chemotherapy SLNB has acceptable false-negative rates in patients who were clinically node-negative before treatment 3

Critical caveat for neoadjuvant therapy:

• Micrometastases detected after neoadjuvant therapy indicate non-pathological complete response and require different management than treatment-naïve micrometastases 1
• Both pre-chemotherapy clinical and post-chemotherapy pathologic nodal stages must be used to determine local recurrence risk 2

For Clinically Node-Positive Patients

Initial assessment:

• Core biopsy or FNA of clinically suspicious nodes is recommended 2
• If biopsy is negative, proceed with SLNB 2
• If biopsy confirms metastases, Level I and II ALND remains the standard 2

Pathologic Assessment Standards

H&E staining alone should guide treatment decisions:

• Cytokeratin immunohistochemistry should not be routinely performed 2, 1
• Historical and clinical trial data relied on H&E staining, making it the appropriate standard 2
• Use cytokeratin IHC only when H&E staining is equivocal 2

Adequate lymph node sampling:

• At least 10 lymph nodes should be examined for accurate staging when ALND is performed 2
• Level III nodes should only be included if gross disease is apparent in Level I or II nodes 2

Situations Where Axillary Surgery May Be Optional

The following patients may forgo axillary procedures, though they face increased risk for ipsilateral lymph node recurrence:

• Particularly favorable tumors where systemic therapy selection is unaffected by nodal status 2, 1
• Elderly patients 2, 1
• Patients with serious comorbid conditions 2, 1

These patients require either ALND or axillary lymph node irradiation to minimize recurrence risk 2

Morbidity Reduction: The Primary Driver of Change

SLNB provides substantial morbidity reduction compared to ALND:

• 38% risk reduction for lymphedema 1
• Decreased shoulder stiffness and pain 1
• Reduced sensory neuropathy 1
• Minimal morbidity with usually no formal exercise required for return to full function 2

Post-ALND rehabilitation is essential:

• Formal exercise training should begin immediately to prevent frozen shoulder 2
• Avoid shoulder immobilization, arm slings, or wraps 2
• Physical therapy should be instituted by 6-8 weeks if full shoulder function is not achieved 2

Critical Pitfalls to Avoid

Contraindications to SLNB:

• Pregnancy 2
• Multicentric carcinomas 2
• Lack of access to experienced sentinel lymph node team 2

Technical requirements:

• Both technetium sulfur colloid and blue dye mapping improve identification rates 2
• If sentinel node cannot be identified, formal ALND should be performed 2

Special consideration for tumor bed localization:

• Percutaneously placed clips under mammographic or ultrasound guidance should be used before neoadjuvant chemotherapy to localize the original tumor volume 2
• This aids in post-chemotherapy resection when complete or near-complete responses occur 2