Monocyte-to-lymphocyte ratio as predictor of cancer therapy-related cardiotoxicity in patients with breast cancer: a pilot cohort study

Background Elevated pre-treatment baseline inflammation has been associated with cancer therapy-related cardiac dysfunction (CTRCD) in patients with breast cancer. Monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio and systemic immune-inflammation index (NLR × platelets) have emerged in clinical context as markers of disease-related inflammation. Objectives To evaluate development of CTRCD according to pre-treatment blood inflammatory biomarkers in patients with breast cancer. Methods Pilot cohort study including consecutive female patients ≥ 18 years with HER2-positive early breast cancer who consulted at the institution's breast oncology outpatient clinic between march/2019 and march/2022. CTRCD: absolute reduction in LVEF > 10% to below 53% (2D-echocardiogram). Survival analysis was performed using Kaplan–Meier curves, compared by the log-rank test, and discrimination ability was evaluated through AUC-ROC. Results Forty-nine patients (53.3 ± 13.3 y) were included and followed-up for a median of 13.2 months. CTRCD was observed in 6 (12.2%) patients. Patients with high blood inflammatory biomarkers had lower CTRCD-free survival (P < 0.050 for all). MLR showed statistically significant AUC (0.802; P = 0.017). CTRCD was observed in 27.8% of patients with high MLR versus 3.2% with low MLR (P = 0.020); negative predictive value was 96.8% (95%CI 83.3–99.4%). Conclusion In patients with breast cancer, elevated pre-treatment inflammatory markers were associated with increased risk of cardiotoxicity. Among these markers, MLR had good discriminatory performance and high negative predictive value. The incorporation of MLR might improve risk evaluation and selection of patients for follow-up during cancer therapy.