Impact of Total and Positive Lymph Node Count on Recurrence in Young Women with Node-Positive Breast Cancer Undergoing Neoadjuvant Chemotherapy

BACKGROUND: Axillary management after neoadjuvant chemotherapy (NAC) in node-positive breast cancer remains controversial. This study assessed the association between total lymph node count, in the context of metastatic lymph node count and lymph node ratio (LNR), and recurrence after NAC in a cohort of young women with node-positive breast cancer. METHODS: Retrospective data were analyzed from 274 women aged ≤ 45 years diagnosed with clinical T1-3, N1-3, M0 invasive breast cancer between January 2010 and December 2023 who received NAC before undergoing surgery at our institution. Primary outcomes were recurrence and overall survival. Total lymph node counts across three LNR tiers were compared between women with at least one metastatic node out of at least three retrieved nodes who did and did not develop recurrence. RESULTS: Patients who developed a recurrence presented with more advanced clinical T (p < 0.001) and N (p = 0.01) staging and had greater residual burden of disease in both the breast (p < 0.001) and the lymph nodes (p < 0.001) than did patients with no recurrence. There was no significant correlation between total number of lymph nodes excised and recurrence in women with at least one metastatic node out of at least three examined nodes in any of the low (p = 0.39), intermediate (p = 0.47), or high (p = 0.67) LNR tiers. CONCLUSION: Tumor biology, chemoresistance, and residual tumor burden after NAC may influence oncologic outcomes more than the number of nodes removed or the extent of nodal surgery. Prospective, large-scale, long-term studies are needed to rigorously address this question, particularly in this young, high-risk population.