Frequency and Risk Factors of Cancer Therapy-Related Cardiac Dysfunction in Patients Receiving Chemotherapy: A Prospective Cohort Study at a Tertiary Centre.

Background: Cancer therapy-related cardiac dysfunction (CTRCD) is an increasingly recognised consequence of contemporary oncological treatment. Left ventricular ejection fraction (LVEF) is insensitive to subclinical myocardial injury, and locally validated thresholds for global longitudinal strain (GLS) are lacking in Vietnamese patients. Objectives: To determine the frequency and risk factors of CTRCD in patients receiving chemotherapy, and to validate a localised GLS threshold and a biomarker-based surveillance strategy for early detection. Methods: We conducted a prospective cohort study of 235 patients at Cho Ray Hospital (September 2023-December 2025). Patients were assessed at baseline and every three months with two-dimensional speckle-tracking echocardiography (GLS), high-sensitivity troponin T (hs-TnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). CTRCD was defined by international consensus criteria. Diagnostic accuracy was assessed using receiver operating characteristic analysis; as the outcome was common, associations were quantified as risk ratios (RR) with 95% confidence intervals (CI) estimated by modified Poisson regression. Results: CTRCD occurred in 82 patients (34.9%). Incidence was highest with anthracyclines (41.2%) and HER2-targeted therapy (37.2%). A relative GLS reduction ≥12.1% predicted CTRCD with 73% sensitivity and 83% specificity. hs-TnT achieved a 100% negative predictive value (NPV), and combining GLS with hs-TnT in parallel retained a 100% NPV. Hypertension (RR 2.50, 95% CI 1.78-3.50), coronary artery disease (RR 2.47, 95% CI 1.82-3.35) and dyslipidaemia (RR 2.10, 95% CI 1.49-2.97) were associated with CTRCD. HFA-ICOS stratification was strongly predictive, with a stepwise increase in risk up to the very-high-risk category (RR 18.6, 95% CI 7.94-43.6 versus low risk; 100% event rate). Conclusions: CTRCD affected one-third of patients. A locally validated GLS threshold combined with hs-TnT enables early, resource-efficient detection, supporting a shift from reactive to proactive cardiac surveillance.