Metastatic Lymph Node Ratio and Log Odds of Positive Nodes Versus Pathologic Nodal Stage in Breast Cancer With Residual Axillary Disease After Neoadjuvant Chemotherapy: A Retrospective Cohort Study

Background and Objectives: Residual axillary disease after neoadjuvant chemotherapy (NACT) challenges prognostication with conventional pathologic nodal (pN) staging. We compared the prognostic value of the metastatic lymph node ratio (mLNR) and the log odds of positive nodes (LODDS) versus pN in ypN+ breast cancer. Methods: We retrospectively analyzed 276 stage IIB–III patients (2010–2022) with residual nodal metastasis after NACT and surgery. Survival was evaluated with Kaplan–Meier and Cox models. Discrimination was summarized by AUC (ROC) with 95% CIs; pairwise DeLong tests compared mLNR versus LODDS. Primary analyses treated mLNR/LODDS as continuous variables; cutoff-based sensitivity analyses used 23.7% and −1.24, respectively. Results: Median dissected nodes were 17 (IQR 13–22); median positive nodes were 3. High LODDS (>−1.24 vs ≤−1.24) independently associated with shorter DFS (HR 1.69, 95% CI 1.10–2.63; p=0.017). mLNR and LODDS showed similar, moderate discrimination for OS/DFS (AUC ≈0.60–0.62), with no significant differences by DeLong testing. Classical adverse features (residual breast tumor, triple-negative subtype, grade III) remained independently prognostic. Conclusions: In ypN+ disease after NACT, mLNR and LODDS perform at least comparably to pN, offering similar, moderate prognostic discrimination without clear superiority of one metric. Routine reporting of both may aid risk communication; subgroup signals are hypothesis-generating and warrant external validation.