Combined role of the neutrophil/lymphocyte ratio and Neo-Bioscore in neoadjuvant therapy in HER2-positive early breast cancer

e12613 Background: High neutrophil/lymphocyte ratio (NLR) is considered a poor prognostic factor in triple negative breast cancer but its role in HER2-positive early breast cancer (eHBC) and its relationship with Neo-Bioscore (Nb) scale (NbS) in neoadjuvant therapy (NeoT) has not been established. They could be predictive factors of response to double antiher2 blocking with Pertuzumab (Pz) and Trastuzumab (Tz). Methods: The efficacy of Chemo-trastuzumab (ChTz) versus Chemo-trastuzumab-pertuzumab (ChTzPz) was assessed in patients with eHBC treated at our center. We performed a comparative analysis of the pathological complete response (pCR) according to pre-treatment NLR and clinical NbS (Grade + clinical stage + estrogen receptor (ER) previous to NeoT) Univariate and multivariate retrospective study were performed using xi-square and binary logistic regression (v21 SPSS software). Results: 150 patients (Pts) with stage IIA to IIIC HBC were treated from 2014 to 2022. Mean age 52 years. 83 Pts (55.3%) received Chem-Tz and 67 Pts (44.7%) Chem-Tz-Pz. In the overall sample, the pCR was higher in the Tz-Pz group, 60% Vs 40%; OR 3.05 (95% CI 1.5-5.9). In the NLR >2 subgroup, pCR was higher in Pts treated with Pz-Tz, 66.7% vs 33.3%; OR 4.2 (95% CI 1.5 – 11.07) If we combine Pts with both NLR ≥2 and clinical Nb ≥2, the pCR was significantly higher in the Tz-Pz group, 68.4% vs 11.8%; OR 16.25 (95% CI 2.7-94.8). In the multivariate analysis, Nb≥2, NLR ≥2 and double blockade with Pz are related to an increase in pCR (OR 1.29, OR 1.076 and OR 2.90 respectively), with significance for Pz (p=0.001). Conclusions: In our review, the combined use of Pz-Tz proves to be a more effective treatment than simple Tz blockade in the treatment of poor prognosis breast cancer. High NLR, despite being a poor prognostic factor, seems to be a predictor factor of pCR in Pts treated with Pz-Tz. The increase in NLR and clinical NbS are factors to take into account to predict the efficacy of NeoT in eHBC Pts. [Table: see text]