No Axillary Surgical Treatment in Clinically Lymph Node Negative Patients on Ultrasonography After Neoadjuvant Chemotherapy: A Prospective, Phase III Clinical Trial
NEO-NAUTILUS is a prospective, multicenter, randomized phase III clinical trial to evaluate whether omitting axillary lymph node surgery (ALND or SLNB) in clinically lymph node-negative breast cancer patients after neoadjuvant chemotherapy is non-inferior to performing SLNB in terms of 5-year disease-free survival.
• Women aged ≥19 years.
• Histologically confirmed invasive breast carcinoma treated with neoadjuvant chemotherapy.
• Clinical staging prior to NAC: cT1-3, cN0, M0 (AJCC 8th Edition).
• If pre-NAC staging is cT1-3, cN1, M0, must meet the following criteria:
‣ HER2-positive or triple-negative breast cancer (TNBC).
⁃ At least 30% reduction in tumor size on MRI after NAC (comparing pre- and post-NAC MRI).
• Negative axillary lymph node status on ultrasound after NAC.
• Planned for breast-conserving surgery with completed neoadjuvant chemotherapy (at least half the planned regimen must be completed).
• ECOG performance status of 0-2.
• Signed written informed consent before enrollment.