BACKGROUND: This study aims to evaluate the predictive significance of platelet lymphocyte ratio (PLR), neutrophillymphocyte ratio (NLR), lymphocyte monocyte ratio (LMR), systemic immune-inflammation (SII), prognostic nutritional index (PNI), haemoglobin, albumin, lymphocyte, and platelet (HALP) score and lactate dehydrogenase to albumin ratio (LAR) for pCR in breast cancer with neoadjuvant chemotherapy (NACT). METHODS: A total of 121 patients who received NACT between February 2012 and November 2021 were included. LAR, NLR, PLR, MLR, SII, PNI and HALP were calculated using formulas. The cut-off value for markers was obtained by Receiver operating characteristic curve (ROC) analyses. Independent predictive factors for pCR were determined using multivariate regression analysis. RESULTS: The pCR rate was achieved in 31.4% of patients. Median values of NLR, PLR, MLR, SII, PNI and HALP were similar in pCR (+) and pCR (-) (p>
0.05). The median LAR value was significantly higher in pCR (+) than in pCR (-) (50.80 vs 42.62, respectively (p=0.002)). The optimal cut-off value of LAR was 46.27. Multivariate analysis showed that LAR ≥46.27 and HER-2 positivity were the independent predictive factors for pCR [OR=2.851 (95% CI=1.142-7.119, P=0.025), OR=3.431 (95% CI= 0.163-10.123, P=0.026), respectively]. CONCLUSIONS: LAR is a simple, inexpensive, and convenient method for predicting pCR in breast cancer with NACT.