Pathologic Complete Response After Neoadjuvant Chemotherapy in Node-Positive Breast Cancer Patients: Regional Analysis of the Breast and Axilla

Background and Objectives: Pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) is a strong prognostic marker in breast cancer and may guide de-escalation of axillary surgery. This study evaluates breast, axillary, and overall pCR rates in initially node-positive patients and examines clinicopathologic predictors of response. Materials and Methods: We retrospectively reviewed 212 women with node-positive invasive breast cancer treated with NAC followed by surgery between February 2019 and July 2025. Breast pCR was defined as ypT0/Tis, axillary pCR as ypN0, and overall pCR as simultaneous clearance of invasive disease in both regions. Associations between pCR and clinical stage, tumor characteristics, and molecular subtypes were analyzed. Results: Breast, axillary, and overall pCR rates were 32%, 61%, and 29%, respectively. Axillary pCR exceeded breast pCR across all subtypes (p