Anthracycline-Induced Cardiomyopathy in Breast Cancer Patients in Oman: A retrospective study.

Objectives: Anthracyclines are widely used in the treatment of breast cancer. One of the known adverse effects of anthracyclines is anthracycline-induced cardiomyopathy. Studies done worldwide showed that the prevalence of chemotherapy-induced cardiomyopathy is approximately 9%. However, studies evaluating this complication prevalence, risk factors and cumulative dose are lacking in Oman. This study aimed to investigate the prevalence of anthracycline-induced cardiomyopathy among breast cancer patients in Oman. Methods: This retrospective study included all breast cancer patients who received anthracycline-based chemotherapy exclusively between September 2008 and December 2020 at Sultan Qaboos University Hospital in Muscat. Patients with partial treatment, coexisting heart failure and who did not receive anthracycline as part of the chemotherapy regimen were excluded. Chemotherapy-induced cardiomyopathy was defined as a drop of left ventricular ejection fraction >10% from the patient's baseline during or after receiving anthracycline-based chemotherapy. Results: A total of 385 patients were included in this study of which 39 (10.1%) developed cardiomyopathy after exposure to anthracyclines. The mean cumulative dose of doxorubicin among these patients was 239 mg/m2 (epirubicin was converted to doxorubicin equivalent dose). Univariate analysis showed that the risk of anthracycline-induced cardiomyopathy was influenced by cardiovascular risk factors such as hypertension (33.3%), diabetes (25.6%), dyslipidaemia (20.5%) and previous cardiovascular medications use (10.3%). Trastuzumab exposure significantly correlated with an increased risk of developing cardiomyopathy (P < 0.001). However, multivariate analysis did not show any significant association. Conclusions: Anthracycline-induced cardiomyopathy was influenced by various cardiovascular risk factors as well as trastuzumab exposure. Further studies are recommended to investigate the prevention and management of anthracycline-induced cardiomyopathy.