Mean platelet volume-to-albumin ratio as a predictor of pathological complete response in HER2-positive breast cancer undergoing neoadjuvant chemotherapy

To evaluate the predictive value of the mean platelet volume–to–albumin (MPV/Alb) ratio for pathological complete response (pCR) in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC) treated with neoadjuvant chemotherapy (NACT). In this retrospective single-center study, 139 consecutive patients with HER2-positive breast cancer who received dual anti-HER2 therapy combined with anthracycline- and taxane-based neoadjuvant chemotherapy between December 2022 and February 2025 were included. Clinicopathological variables, immuno-inflammatory parameters, and the MPV/Alb ratio were analyzed. Predictors of pCR were assessed using univariable and multivariable logistic regression. Discriminative performance and an optimal cut-off for MPV/Alb were determined by receiver operating characteristic (ROC) analysis. The median age was 50 years (range, 26–79), and pCR was achieved in 54.7% of patients. On univariable analyses, estrogen receptor (ER) status, progesterone receptor (PR) status, and MPV/Alb were associated with pCR. In multivariable analysis, only MPV/Alb remained an independent predictor of pCR (p = 0.012; odds ratio OR, 0.388; 95% confidence interval CI, 0.185–0.813). ROC analysis identified an optimal MPV/Alb cutoff of 2.32 (AUC 0.626; 95% CI 0.535–0.720; p = 0.048), yielding 64.5% sensitivity and 58.7% specificity. The MPV/Alb ratio may serve as an independent predictor of pCR in HER2-positive BC undergoing NACT. As a readily obtainable, low-cost composite derived from routine laboratory tests, MPV/Alb could aid risk stratification and treatment decision-making in clinical practice.