Early detection of cardiac dysfunction in patients with breast cancer receiving antitumor therapy

Background Myocardial dysfunction that develops during or after completion of anticancer therapy is an increasing public health problem. Monitoring the development of subclinical cardiotoxicity is critical to prevent the onset of heart failure (HF). The purpose of this study is to enable the early detection of heart damage and dysfunction in patients who have undergone surgery for breast cancer and are receiving antitumor therapy with anthracyclines (mainly Doxorubicin), radiation therapy, and long-term therapy with Anastrozole. Methods We monitored 42 women with breast cancer (mean age 46 ± 9 years) who were receiving anthracycline chemotherapy, radiation therapy, and long-term Anastrozole treatment. The clinical examination included physical, instrumental, and laboratory assessments, including the determination of high-sensitivity cardiac troponin T (hs-TnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP). Tissue Doppler imaging was used to determine e´sep — the velocity of the interventricular septum during early diastole, e´lat. — the velocity of the lateral mitral annulus during early diastole, E/e´ — the ratio of mitral inflow velocity (E) to the average velocity of the mitral annulus, and IVRT — isovolumic relaxation time of the left ventricle. The patients were examined before the initiation of chemotherapy and surgery, then at 3 and 6 months after receiving anticancer therapy. The studies were conducted based on simple open protocols using SPSS 16.0. Results After 3-6 months, 42% of patients reported palpitations, 19% had changes in blood pressure, 48% experienced chest pain, and 56% had shortness of breath, especially with minor physical activity. Sinus tachycardia was found in 37% of patients, ectopic activity in 33%, and QT interval prolongation in 14% of patients. Echocardiogram analysis revealed a slight decrease in left ventricular ejection fraction in 44% of patients. Among those receiving chemotherapy for 3-6 months, 89% showed progressive diastolic dysfunction of the left ventricle. Specifically, e´lat. decreased from 11.2-12.4 cm/s to 8.8-9.6 cm/s at 3 months and 6.2-8.1 cm/s at 6 months; e´sep. decreased from 8.4-10.2 cm/s at 3 months to 6.6-7.4 cm/s at 3 months and 5.7-6.8 cm/s at 6 months; E/e´ increased from 7-8 cm/s at 3 months to 9-11 cm/s at 3 months and 12-14 cm/s at 6 months; IVRT increased from 70-90 ms to 90-100 ms at 3 months and ≥110 ms at 6 months. Biomarker analysis showed that at 6 months, 49% of patients had elevated hs-TnI levels (≥7 ng/L), and 51% had elevated NT-proBNP levels (≥125 ng/mL). Conclusion The onset of diastolic dysfunction and elevated hs-TnI and NT-proBNP levels in breast cancer patients receiving anticancer therapy suggests the development of HF. Often, an asymptomatic phase of heart dysfunction predominates, during which preventive measures can be taken to prevent the onset or progression of HF.