Annotation

  In Kazakhstan, breast cancer remains the leading cause of cancer morbidity and mortality among women. The presented case series aims to summarize cardiovascular events that resulted in discontinuation or suspension of anthracycline-based chemotherapy during an ongoing project on studying the cardiotoxic effects.

  Case 1: Classic acute cardiotoxicity with asystole. Patient Sh., 46 years old, was admitted with a baseline left ventricular ejection fraction (LVEF) of 64% and global longitudinal strain (GLS) of 22.4%. After the first dose of doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2, the patient experienced two episodes of asystole. Trimetazidine was prescribed at a dose of 80 mg. Eventually, Sh. completed the courses of anthracycline therapy after a 1-month delay at a cumulative dose of 455 mg/m2.

  Case 2: Subacute cardiotoxicity with ventricular extrasystole. Patient Zh., aged 47, developed single, paired, and group ventricular extrasystoles after the 2nd course of chemotherapy with doxorubicin 200 mg/m2 (23 days after admission). Carvedilol was prescribed at 25 mg twice daily and Trimetazidine at 80 mg once a day. After one month of monitoring, ventricular extrasystoles disappeared. The patient completed chemotherapy at a cumulative dose of 400 mg/m2, with a 1-month delay.

  Case 3: Severe cardiotoxicity due to pre-existing cardiovascular disease with discontinuation of chemotherapy. Patient M., aged 58, was referred to the very high-risk group for developing atrial fibrillation and heart failure with an LVEF of 51%. M. received Enalapril 5 mg twice daily, Bisoprolol 5 mg, Eplerenone 50 mg, Dapagliflozin 10 mg, and Dabigatran 150 mg twice daily. After three months, anthracycline therapy was canceled at a cumulative dose of 260 mg/m2 due to deterioration of the patient's condition (LVEF 41%).

  Conclusion: Discontinuation or delay of vitally needed chemotherapy in breast cancer patients deteriorates their prognosis for survival. Patients should be constantly monitored during and after anticancer treatment.

Keywords: anthracyclines, chemotherapy, cardiotoxicity, Kazakhstan, case series