What trial supports omitting axillary lymph node dissection (ALND) and sentinel lymph node biopsy (SLNB) in an elderly female patient with stage IIA, luminal A subtype breast cancer?

ACOSOG Z0011 Trial

The trial that supports omitting axillary lymph node dissection (ALND) in patients with early-stage breast cancer and limited sentinel lymph node involvement is the ACOSOG Z0011 trial. 1, 2

Trial Design and Population

The ACOSOG Z0011 was a phase III noninferiority randomized controlled trial that enrolled 891 women with specific characteristics: 1, 2

• Tumor characteristics: Clinical T1-T2 invasive breast cancer (tumors ≤5 cm) 1
• Nodal status: Clinically node-negative by physical examination with 1-2 positive sentinel lymph nodes discovered at surgery 1, 2
• Surgical approach: All patients underwent breast-conserving surgery (lumpectomy) 1, 2
• Adjuvant therapy: All received whole-breast radiation therapy and appropriate systemic therapy 1, 2

Patients were randomized to either completion ALND (n=446) or sentinel lymph node biopsy (SLNB) alone without further axillary surgery (n=445). 1

Key Trial Results

Long-Term Outcomes (10-Year Follow-Up)

The trial demonstrated that SLNB alone was noninferior to completion ALND across all major endpoints: 1, 2

• Overall survival: 86.3% in SLNB-alone group vs 83.6% in ALND group (HR 0.85,95% CI 0-1.16; noninferiority P=0.02) 1
• Disease-free survival: 80.2% in SLNB-alone group vs 78.2% in ALND group (HR 0.85,95% CI 0.62-1.17; P=0.32) 1
• Locoregional recurrence: 5.3% in SLNB-alone group vs 6.2% in ALND group (P=0.36) 1
• Ipsilateral axillary recurrence: Only 1.5% in SLNB-alone group vs 0.5% in ALND group (P=0.28) 2

Clinical Application to Your Patient

For an elderly female patient with stage IIA, luminal A (hormone receptor-positive/HER2-negative) breast cancer, the Z0011 trial provides strong evidence to omit ALND if she meets the eligibility criteria. 2, 3 However, there are important considerations specific to elderly patients:

Complete Omission of Axillary Surgery

Beyond Z0011, two more recent trials (SOUND and INSEMA) support omitting even SLNB entirely in carefully selected low-risk patients: 2, 3

• SOUND trial: Demonstrated non-inferiority of no axillary surgery compared to SLNB in 1,405 women with tumors ≤2 cm and negative preoperative axillary ultrasound, with 5-year locoregional relapse rates of only 1.6% without surgery vs 1.7% with SLNB 2
• INSEMA trial: Confirmed non-inferiority in 4,858 patients with cN0, T1-T2 invasive breast cancer undergoing breast-conserving surgery, showing 5-year invasive disease-free survival of 91.9% without axillary surgery vs 91.7% with SLNB 2

Specific Recommendations for Elderly Patients

The Society of Surgical Oncology's Choosing Wisely guidelines explicitly recommend against routine SLNB in clinically node-negative, hormone receptor-positive breast cancer patients aged ≥70 years. 3 This is particularly relevant for your patient scenario because:

• Age-related considerations: Elderly patients (≥70 years) with favorable tumor biology may safely omit SLNB when axillary staging will not alter systemic treatment decisions 3
• Reduced morbidity: Omitting axillary surgery eliminates risks of lymphedema (1.8% vs 5.7%), arm/shoulder mobility restriction (2.0% vs 3.5%), and pain (2.0% vs 4.2%) 2
• Stage IIA luminal A context: For hormone receptor-positive, HER2-negative disease in elderly patients, endocrine therapy decisions are typically based on tumor characteristics rather than nodal status 3

Supporting Evidence from Complementary Trials

The Z0011 findings have been validated by multiple additional randomized controlled trials: 1, 2

• IBCSG 23-01 trial: Demonstrated noninferiority of omitting ALND in patients with sentinel node micrometastases, with 10-year disease-free survival of 76.8% without ALND vs 74.9% with ALND (HR 0.85,95% CI 0.65-1.11) 1
• SENOMAC trial: Confirmed noninferiority of SLNB alone in 2,540 patients with 1-2 sentinel node macrometastases, showing 5-year recurrence-free survival of 89.7% with SLNB alone vs 88.7% with ALND 1

Critical Implementation Points

When applying Z0011 criteria, ensure ALL of the following are met: 1, 2

• Clinical T1-T2 tumors (not T3) 1
• Clinically node-negative by examination 1
• Only 1-2 positive sentinel lymph nodes (not ≥3) 1
• Breast-conserving surgery performed (not mastectomy) 1, 2
• Whole-breast radiation therapy planned 1, 2
• Appropriate systemic therapy will be administered 1

A common pitfall is attempting to apply Z0011 criteria to patients undergoing mastectomy—this is NOT supported by the trial data. 2