Association between baseline hemoglobin levels and pathological complete response in 404 female breast cancer patients undergoing neoadjuvant therapy in Western Guangdong region: a retrospective cohort study

Background Breast cancer is the most common female malignancy globally and a leading cause of cancer-related death. In China, an estimated 350,000 new cases were reported in 2022, with more than 65% of patients aged ≤35 years diagnosed at stage II or higher. Neoadjuvant therapy (NAT) is recommended by NCCN guidelines for operable breast cancer with clinical stage ≥T2, node-positive, HER2-positive, or triple-negative disease. Achieving pathological complete response (pCR) after NAT is associated with improved event-free survival (EFS), but benefits vary widely, underscoring the need for predictive biomarkers. Objective To evaluate the association between baseline hemoglobin (Hb) levels and pCR and EFS in female breast cancer patients from Western Guangdong, China. Method This retrospective study included 404 invasive breast cancer patients who received NAT between 2014 and 2024. Multivariate logistic regression and Cox models were used to assess Hb’s relationship with pCR and EFS. Dose-response was analyzed using restricted cubic splines. Patients were stratified by Hb tertiles: Q1 (123 g/L), Q2 (123–133 g/L), Q3 (133 g/L). Kaplan-Meier curves were generated for survival analysis. Results The pCR rate was 37.1%. Each 1 g/L increase in Hb was associated with a 2% increase in pCR probability (OR = 1.02, 95% CI: 1.01–1.04). Subgroup analyses confirmed consistency across molecular subtypes, menopausal status, and BMI. Multivariate Cox analysis showed each 1 g/L Hb increase reduced event risk by 2% (HR = 0.98, 95% CI: 0.97–0.99). During median follow-up, 83 (20.5%) patients had events; EFS differed significantly across Hb tertiles (log-rank P 0.001). Conclusion Baseline Hb demonstrates a significant linear positive correlation with pCR and EFS, supporting its potential as a simple, low-cost biomarker for predicting NAT benefit in breast cancer patients.