Predictive biomarkers for pathological complete response in early-stage triple negative breast cancer following neoadjuvant chemotherapy.

598 Background: Identifying predictive biomarkers for early-stage triple negative breast cancer (TNBC) is essential for tailoring neoadjuvant chemotherapy (NACT) strategies effectively. Methods: We investigated potential clinical and pathological biomarkers in early-stage TNBC patients who underwent NACT regimens with anthracyclines and taxanes at a single cancer center. Medical records were scrutinized for clinical and laboratory data, with categorical variables analyzed using Fisher’s exact test. Logistic regression assessed factors associated with pathological complete response (pCR). Sensitivity and specificity of the biomarkers were explored using receiver operating characteristics (ROC) curve analyses. Results: Among 110 TNBC patients receiving anthracycline- and taxane-based NACT with complete pathology data, the median age was 48 years, 60% had stage III tumors, and 30.9% achieved pCR. Stromal tumor infiltrating lymphocytes (TILs) > 10% were observed in 54.5%, 32.7% had TILs ≥30%, and 90.9% had Ki67 ≥ 50%. Univariate analysis showed no association between pCR and TILs >10% (p=0.5), Ki67 ≥ 50% (p=0.4), anatomic stage (p=0.06), eosinophil-to-lymphocyte ratio (p=0.3), platelet-to-lymphocyte ratio (p=0.08), age (p=0.5), grade (p=0.6), or HER2 status (p=0.6). Neutrophil-to-lymphocyte ratio (NLR) was significantly associated with pCR in both univariate (OR 3.92; 95% CI 1.67 - 9.57; p=0.002) and multivariable analyses (Table). No association was observed between NLR ≤ 1.76 and TILs, anatomic stage, or Ki67. The optimal NLR cutoff using ROC curve was 1.76, yielding 60.6% sensitivity and 71.8% specificity for pCR. NLR cutoffs of ≤ 1.43 had specificities higher than 85%. Although TILs value was not associated with pCR in the regression model, high TILs value (≥50%) yielded a specificity of 89.4% for pCR. Conclusions: NLR emerged as a significant and independent predictor of pCR in early-stage TNBC. Prospective studies should explore this readily available biomarker in assessing neoadjuvant strategy responses. Moreover, high specificities for pCR were observed with NLR ≤ 1.43 and TILs ≥ 50%, representing cutoff values that could be explored for treatment de-escalation. Table: see text