The impact of trastuzumab therapy and cardiovascular risk factors on cardiac function in HER2- positive breast cancer patients

Abstract

Background: Aside from the clinical benefits of trastuzumab in treating HER2- positive breast cancer,cardiotoxicity is identified as a major side effect. Cardiac function should be closely monitored before,during, and after trastuzumab therapy.Aim: To assess cardiac function during trastuzumab therapy and the effect of risk factors (RF) forcardiotoxicity and cardiovascular (CV) diseases in HER2-positive breast cancer patients.Materials and Methods: Ninety-six HER2-positive female breast cancer patients (mean age, 59.57±9.6years) were enrolled in the study. At the time, they were on sequential therapy with anthracyclines (IVto VI cycles) within the FAC regimen (fluorouracil 500 mg/m 2 , doxorubicin 50 mg/m 2 , cyclophosphamide500 mg/m 2 ) applied per 21 days, and after that, trastuzumab therapy (6 mg/kg of body weight, per21 days for one year). In all patients, blood pressure (BP), heart rate (HR), electrocardiographic andechocardiographic parameters (left ventricular ejection fraction – LVEF (%), fractional shortening –FS (%), end-diastolic diameter – EDD (mm), and left ventricular mass – LVM (g)) were assessed at thebeginning and after the therapy with trastuzumab.Results: There were no significant changes in arterial BP before and after trastuzumab in the examinedpatients. Ectopic beats (EB) were registered during the therapy in 11 patients, supraventricular in 7, andventricular extrasystoles in 4 patients on the electrocardiogram (ECG). In most of the patients with EB inthe middle of the treatment period with trastuzumab, sinus tachycardia was also recorded. At the end oftrastuzumab therapy in the examined group, LVEF decreased by 1.73 %, FS by 0.86 %, EDD increasedby 1.26 mm, and LVM increased by 9.6 g. Cardiotoxicity was registered in 4 (4.17%) patients. Greaterleft ventricular dysfunction was observed in older patients, patients with prior radiation therapy, andthose with three or more cardiovascular risk factors (CVRF).Conclusion: This study shows that the treatment with trastuzumab does not significantly affect BPand ECG changes. The rate of cardiotoxicity after trastuzumab therapy was low and was expressedthrough reduction of LVEF, an increase in EDD, and LVM. In patients with three or more CVRFs, therewas a higher decrease of LVEF than in patients without any cardiovascular risk factors