Assessment of Cardiotoxicity incidence in patients receiving HER-2-targeted therapies for breast cancer in Saudi Arabia

Background: Human Epidermal growth factor Receptor (HER2) targeting therapies may raise the risk of decreased left ventricular ejection fraction (LVEF), which might appear clinically as heart failure. Trastuzumab's incidence of cardiotoxicity in individuals with a history of anthracycline usage varies between 4% and 18.6%, with 0.4–4.1% of patients developing serious heart failure. The increasing number of breast cancer survivors as a consequence of HER2-targeted treatment has necessitated the long-term care of cardiotoxicity induced by iatrogenic chemotherapy. Method: This retrospective study included all HER-2-positive breast cancer patients aged 18 or older who received at least one dose of HER-2-targeting treatment between 2016 and 2020. The primary endpoint was to determine the incidence of cardiotoxicity induced by HER-2 targeted treatment, which was defined as LVEF < 50% with LVEF decline by 10%, LVEF drop by > 15%, or the onset of symptomatic heart failure. The secondary endpoints were the proportion of patients with LVEF between 50% and 55% at baseline who developed cardiotoxicity, the proportion of patients who temporarily or permanently discontinued HER-2 targeting therapy due to HF, the proportion of patients who developed HF and were treated with HF medications, and the proportion of patients who received HF medications for cardiotoxicity and continued their HER-2 targeting therapy. The development of a hospital protocol for monitoring and managing cardiotoxicity in patients receiving HER-2-targeted treatments was another secondary outcome. Results: A total of 212 patients were included in the research, with a median age of 56.5 years and an interquartile range of 43–58 years. 105 patients with early breast cancer (EBC), and 107 patients with metastatic breast cancer (MBC). Twenty-two patients (10.37%) suffered cardiotoxicity with HER-2-specific treatment. Thirteen of the 22 patients (6.13%) had asymptomatic heart failure with a decrease in LVEF from baseline of more than 10% to less than 50%. Five patients (2.35%) with LVEF less than 40% had asymptomatic heart failure, while four patients (1.88%) presented with symptomatic heart failure regardless the LVEF decline. HER-2 targeted treatment was discontinued temporarily in 3 (13.63%) patients and permanently in 4 (18.18%) patients due to cardiotoxicity. The remaining fifteen patients resumed their treatment without interruption. Only 13 out of 22 patients were referred to cardiologists and prescribed medicines for heart failure. Conclusion: Close monitoring of LVEF for patients receiving HER-2 targeting therapy can assist healthcare providers to initiate anti-heart failure medications to prevent deterioration of LVEF and maintain Her-2 targeting therapy.