Neutrophil-to-Lymphocyte Ratio Predicts Pathological Complete Response in Triple-Negative Breast Cancer Treated With Neoadjuvant Pembrolizumab Plus Chemotherapy.

BACKGROUND: Neoadjuvant systemic therapy (NST) is the standard of care for high-risk early triple-negative breast cancer (TNBC). Although pathological complete response (pCR) is strongly associated with improved survival, reliable and accessible predictors of response remain limited. The aim of this study was to evaluate whether peripheral blood immune markers and tumor-infiltrating lymphocytes (TILs) can predict pCR in patients with TNBC treated with neoadjuvant pembrolizumab plus chemotherapy. MATERIALS AND METHODS: In this single-institution retrospective study, 60 patients with stage II-III TNBC received NST according to the KEYNOTE-522 regimen followed by curative surgery. Pretreatment neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and TIL levels were assessed. Associations with pCR were analyzed using logistic regression models. RESULTS: Thirty-six patients (60.0%) achieved pCR. In the univariate analysis, low NLR, high TILs, and histological type were significantly associated with pCR, whereas PLR was not. Multivariate analysis identified low NLR and histological type as independent predictors of pCR. Patients with both low NLR and high TILs demonstrated the highest pCR rate. CONCLUSION: NLR may be a simple and accessible predictor of pCR in patients with TNBC receiving neoadjuvant pembrolizumab plus chemotherapy. Combining peripheral blood immune markers with intratumoral immune parameters may enhance treatment stratification.