Anthracycline-Induced Cardiotoxicity in Breast Cancer Patients: A Five-Year Retrospective Study in 10 Centers.

Background: Cardiotoxicity as a result of anthracycline chemotherapy has been linked to increased morbidity and mortality in breast cancer patients. There is a need for early detection through risk factor identification. To date, no large multicenter study has been conducted to describe the incidence, risk factors and clinical and demographic profiles of breast cancer patients with anthracycline-induced cardiotoxicity (AIC) in the Philippines. Methods: This was a nationwide multicenter retrospective cohort study among adult breast cancer patients who underwent anthracycline chemotherapy from 2015 to 2020 in 10 sites in the Philippines. Baseline characteristics and possible risk factors for AIC were retrieved from medical records and cancer registries. AIC was defined as a reduction of left ventricular ejection fraction (LVEF) by > 10% from baseline to a value of < 53% or the development of overt left ventricular systolic dysfunction or heart failure (HF). Odds ratios from logistic regression were computed to determine risk factors associated with AIC using STATA-15.0 software. Results: Out of 341 patients included, 33 had AIC, accounting for an incidence of 9.68%. Nine patients (2.6%) had clinical HF. AIC patients had a mean age of 53.91 ± 10.84 years. Breast cancer AIC patients were significantly older and had lower body mass index (BMI) than those without AIC. AIC patients had significantly more comorbidities, especially hypertension and atrial fibrillation. Multivariate analysis showed that patients with any preexisting comorbidity are approximately 12.37 times as likely to have AIC, while those with concurrent chemotherapy are 0.07 times or 93% less likely to have AIC. Conclusion: Among adult breast cancer patients undergoing anthracycline chemotherapy, we determined a high incidence of cardiotoxicity at 9.68%. Having preexisting comorbidities gave patients 12 times increased odds of developing anthracycline cardiotoxicity. The presence of concurrent non-anthracycline chemotherapy showed an inverse association with the development of AIC which we attribute largely to patient selection in a retrospective study. The significantly higher propensity for AIC development in patients with preexisting comorbidities may warrant closer monitoring and control of patient comorbidities such as hypertension among patients undergoing anthracycline chemotherapy.