Trastuzumab-induced cardiotoxicity in patients with metastatic HER2-positive breast cancer treated at a reference hospital in Mexico.

Abstract

e13032 Background: In Mexico, breast cancer represents the leading cause of cancer-related death in women, and up to 52% is diagnosed at a metastatic stage. Up to 20-25% of women with breast cancer have overexpression of the human epidermal growth factor receptor 2 (HER2) which is associated with an aggressive behavior. The most relevant adverse effect associated with therapy targeting this receptor is an increase of up to 4 times in the rate of myocardial dysfunction. There is limited research in the Mexican population, especially in the metastatic context. This review is intended to be conducted in the national population, including patients with HER2-positive metastatic breast cancer who have received trastuzumab treatment, to determine the main characteristics of such myocardial dysfunction using the definition of cardiac dysfunction proposed by the International Cardio-Oncology Society (ICOS) in 2021, as well as its current prevalence. Methods: Observational, descriptive, cross-sectional, retrospective study. Medical records of patients diagnosed with metastatic HER2-positive breast cancer between January 2017 and December 2022, who received trastuzumab and had a determination of left ventricular ejection fraction (LVEF) before treatment and at least two LVEF determinations during treatment to determine the presence or absence of cardiotoxicity. LVEF could have been determined by MUGA (Multigated Acquisition Scan) or by echocardiogram. Results: A total of 103 patients were included, with a mean age of 55 years. The found prevalence of cardiotoxicity was 30.09%. Among the most frequent clinical characteristics of these patients were obesity in 32.2% [n= 10], smoking habit in 12.9% [n= 4], and type 2 diabetes in 9.7% [n= 3]. The diagnosis of de novo metastatic disease was 48.4% [n= 15]. A history of ischemic heart disease was present in 3.2% [n= 1], and a frequency of 12.9% [n= 4] of patients with borderline LVEF (50-54%) was reported at baseline, with only 3.2% [n= 1] documented with a baseline LVEF < 50%. The median number of trastuzumab cycles administered during follow-up was 14 cycles, anthracycline therapy was documented in most patients, and previous exposure to thoracic and/or mediastinal radiotherapy with a dose exceeding 30 Gy was found in 35.5% [n= 11]. Referral to cardiology and/or cardio-oncology service was 51.6% [n= 16]. Discontinuation of anti-HER2 treatment was carried out in 3 patients (2.9%). Conclusions: We demonstrated a prevalence of cardiotoxicity from anti-HER2 agents in our population similar to that reported in the international literature. Multicenter studies are necessary to define the prevalence more accurately in the Mexican population, as well as prospective studies to demonstrate the association between cardiovascular risk factors and clinical characteristics with the development of cancer therapy-related cardiac dysfunction.