A COMPARATIVE STUDY OF CARDIOVASCULAR TOXICITY OF EPIRUBICIN AND DOXORUBICIN IN PATIENTS WITH BREAST CANCER.

Patients with breast cancer (BC) are at high risk of cardiotoxicity (CT) due to combination of anticancer treatment.Cardio-vascular (СV) complications lead to the delay or discontinuation of anticancer therapy, which significantlyworsens the prognosis. Anthracyclines (AC) are the main drugs included in most anticancer treatment regimens.Detecting signs of CT at the early stages, when there is no cardiac dysfunction and signs of heart failure (HF), isimportant to develop individualized monitoring and prevention strategies in BC patients.The objective of the study was to investigate the incidence of CT of epirubicin and doxorubicin in the complex BCtherapy, based on monitoring of left ventricular ejection fraction (LV EF), diastolic function of the LV, and to investigate the incidence of signs and symptoms of HF.

Material and methods: The study included 44 BC patients. We analyzed the dynamics of LV EF before the start ofantitumor treatment and within 6 months. A decrease in LVEF of > 10 % (percentage points) or below its thresholdvalue (< 50 %) was considered to be a CT criterion. Patients were divided into 2 groups. Group 1 included patientswith BC who received epirubicin (n = 18), group 2 included BC patients who received doxorubicin in the chemotherapy regimen (n = 26).

Results: Before the start of chemotherapy, LV ejection fraction was normal and did not differ significantly betweenthe groups. During follow-up at 6 months after the start of treatment, in group 1 the proportion of patients with CTaccording to LV EF was 11.1 %, compared with 23.1 % in group 2 (p < 0.05). The number of patients with signsand symptoms of HF was 34.6 % in group 2, that was significantly higher compared with that in group 1 - 11.1 %(p < 0.05). According to the correlation analysis, LV EF in group 2 had an inverse correlation with the dose of doxorubicin (r = -0.67, p < 0.05), with heart rate (r = -0.59, p < 0.05), and with body mass index (r = -0.55, p < 0.05),indicating a negative effect of doxorubicin on the CV system in patients with BC.

Conclusions: The results of the study indicate a significantly higher incidence of LV EF reduction as a CT criterionwhen using doxorubicin in the chemotherapy regimens compared with epirubicin. Myocardial damage as a result ofchronic cardiotoxicity is accompanied by a decrease in LV systolic function and a significantly higher incidence of HF.