154eP Longitudinal inflammatory biomarkers and response to neoadjuvant chemotherapy plus dual HER2-targeted therapy in HER2-positive breast cancer: Results from the PANDA-Breast cancer cohort

Background: Longitudinal evidence linking inflammatory biomarkers (IBs) to neoadjuvant therapy efficacy in breast cancer(BC) is limited.We examined this association in HER2-positive BC using a longitudinal analytic framework. Methods:This study included 294 women with HER2-positive BC.IBs including peripheral blood lymphocyte, neutrophil, monocyte, platelet, albumin, and high-sensitivity C-reactive protein (hs-CRP) were measured prior to each cycle of neoadjuvant systemic therapy.We derived inflammation-related composite indices, including hs-CAR (hs-CRP/albumin ratio), NLR (neutrophil-to-lymphocyte ratio), PLR (platelet-tolymphocyte ratio), and MLR (monocyte-to-lymphocyte ratio).Ordinary linear regression models were applied to evaluate the association between IBs and patients' baseline characteristics.Spearman correlation analysis was used to assess the relationships among IBs.Multivariable logistic regression model was used to assess the associations between IBs and pathological complete response (pCR).We examined the possibility of nonlinearity between IBs and pCR with restricted cubic splines. Results:The mean age was 49.95 years.Overall, 167 women (56.80%, 95% CI: 51.14%-62.46%)achieved pCR following neoadjuvant therapy.The proportion of patients achieving pCR was higher among postmenopausal women than among premenopausal women (60.26% vs. 52.90%).Baseline levels of hs-CRP were associated with age, menopausal status, and clinical stage; baseline neutrophil counts were associated with clinical stage; baseline hs-CAR was associated with menopausal status and clinical stage.A positive correlation was observed between lymphocyte and monocyte counts (Spearman's =0.33, 95%CI:0.20-0.39).Compared with patients in the lowest tertile, those in the second tertile of mean albumin levels had higher odds of achieving pCR (OR Q2vsQ1 =1.97, 95% CI: 1.02-3.77).No statistically significant deviations from linearity were observed in the associations between IBs and pCR.Conclusions: Intermediate levels of albumin may be associated with an increased likelihood of achieving pCR.