Axillary Surgery in Sentinel Node-Positive Breast Cancer After Neoadjuvant Therapy: A Systematic Review and Meta-analysis.

The oncologic value of axillary lymph node dissection (ALND) for residual node-positive (ypN+) breast cancer after neoadjuvant therapy is uncertain when regional nodal irradiation (RNI) is routinely used. We systematically reviewed comparative evidence on locoregional control and survival outcomes with omission versus completion of ALND. PubMed/MEDLINE, Embase, and Cochrane Central were searched from 2000 to 2025 for English-language studies comparing completion ALND with omission of ALND (sentinel lymph node biopsy and/or targeted axillary dissection) among patients with biopsy-proven node-positive breast cancer treated with neoadjuvant therapy who had residual nodal disease at surgery. Two reviewers screened studies and extracted outcomes. We identified 445 initial records for screening and review. Five nonrandomized comparative studies, including 4670 patients, met inclusion criteria and directly compared ypN+ outcomes by axillary surgery extent. In cohorts where RNI was commonly administered, axillary recurrence was uncommon (0.37%-5.7% without ALND and 0.4%-4.8% with ALND). Meta-analysis of comparative studies showed no clear difference in axillary recurrence with omission versus completion of ALND (pooled RR 1.09, 95% CI, 0.47-2.52; P = .80), with moderate heterogeneity (I² = 46%). In selected ypN+ patients treated with RNI, omission of completion ALND appears to yield low axillary recurrence and similar survival outcomes while potentially reducing surgical morbidity. Randomized trials and long-term results of prospective studies are needed to further guide axillary management of patients with residual nodal burden after neoadjuvant therapy.