No Axillary Surgical Treatment in Clinically Lymph Node Negative Patients on Ultrasonography After Neoadjuvant Chemotherapy

Breast Cancer, Neoadjuvant Therapy, Sentinel Lymph Node Biopsy

Omission of axillary surgery after neoadjuvant chemotherapy, Breast cancer, Neoadjuvant chemotherapy, De-escalation, Omission of surgery

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.

Background: * No prospective studies have proven that axillary lymph node surgery improves survival in breast cancer patients. * The ACOSOG Z0011 trial showed that additional axillary dissection did not improve recurrence or survival, even with a 23.7% incidence of non-sentinel node metastases. * NSABP B-32 established the oncologic safety of SLNB, significantly reducing complications like lymphedema compared to axillary dissection. However, SLNB still carries risks of lymphedema, sensory changes, seromas, and infections. * The trend has now shifted toward identifying candidates for omitting axillary surgery to minimize unnecessary complications. * The SOUND trial demonstrated non-inferiority of omitting SLNB in early-stage breast cancer patients with negative axillary ultrasound. Five-year distant metastasis-free survival was comparable between SLNB and no-SLNB groups (97.7% vs. 98.0%). * Improved ultrasound accuracy (e.g., FNR: 13.7% in SOUND; 11.3% in NAUTILUS) and the therapeutic contribution of whole-breast radiation likely support these findings. * Patients with a complete pathological response (pCR) in the breast post-NAC rarely have residual lymph node metastases, reducing the need for axillary surgery. * Single-arm studies (e.g., EUBREAST-01, ASICS, ASLAN) have explored omitting axillary surgery in patients with confirmed breast pCR. However, these studies face limitations due to small sample sizes, single-arm design, and the necessity of axillary surgery if pCR is not achieved. * To address these limitations, the NEO-NAUTILUS trial proposes the first randomized trial to compare disease-free survival and local recurrence rates between patients who omit SLNB (experimental group) and those who undergo SLNB (control group) after NAC, focusing on patients deemed axillary node-negative by ultrasound.

South Korea