no axillary surgical treatment in clinically lymph node negative patients on ultrasonography after neoadjuvant chemotherapy

Conditions: Breast Cancer; Neoadjuvant Therapy; Sentinel Lymph Node Biopsy

Summary: 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.

Eligibility criteria:
inclusion criteria: * 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: 1. her2-positive or triple-negative breast cancer (tnbc). 2. 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. exclusion criteria: * history of any cancer within the past 5 years. * bilateral breast cancer. * patients requiring mastectomy. * tumor size \>5 cm after nac. * male breast cancer. * pregnant or breastfeeding women. * inability to understand and complete questionnaires.

Keywords: omission of axillary surgery after neoadjuvant chemotherapy breast cancer neoadjuvant chemotherapy de-escalation omission of surgery