Nodal Burden and Oncologic Outcomes in Patients With Residual Isolated Tumor Cells After Neoadjuvant Chemotherapy (ypN0i+): The OPBC-05/ICARO Study

Abstract

PURPOSE: The nodal burden of patients with residual isolated tumor cells (ITCs) in the sentinel lymph nodes (SLNs) after neoadjuvant chemotherapy (NAC) (ypN0i+) is unknown, and axillary management is not standardized. We investigated rates of additional positive lymph nodes (LNs) at axillary lymph node dissection (ALND) and oncologic outcomes in patients with ypN0i+ treated with and without ALND. Methods: The Oncoplastic Breast Consortium-05/ICARO cohort study (ClinicalTrials.gov identifier: NCT06464341) retrospectively analyzed data from patients with stage I to III breast cancer with ITCs in SLNs after NAC from 62 centers in 18 countries. The primary end point was the 3-year rate of any axillary recurrence. The rate of any invasive recurrence was the secondary end point. Results: In total, 583 patients were included, of whom 182 (31%) had completion ALND and 401 (69%) did not. The median age was 48 years. Most patients (74%) were clinically node-positive at diagnosis and 41% had hormone receptor-positive/human epidermal growth factor receptor 2-negative tumors. The mean number of SLNs with ITCs was 1.2. Patients treated with ALND were more likely to present with cN2/3 disease (17% v 7%, P