Prospective evaluation of early cardiac damage induced by epirubicin-containing adjuvant chemotherapy and locoregional radiotherapy in breast cancer patients.

Purpose: To evaluate prospectively the cardiotoxic effects of epirubicin-containing adjuvant chemotherapy in breast cancer patients.
Patients and Methods: Patients (median age, 46 years; range, 28 to 55 years) were treated with five cycles of fluorouracil, epirubicin (90 mg/m2), and cyclophosphamide (FEC) (group I, n = 21) or with four cycles of FEC followed by high-dose chemotherapy consisting of cyclophosphamide, thiotepa, and carboplatin (group II, n = 19). Locoregional radiotherapy was applied subsequently. Cardiac evaluation was performed before chemotherapy (T0), 1 month after chemotherapy, 1 month after radiotherapy (T2), and 1 year after start of chemotherapy (T3). Left ventricular ejection fraction (LVEF) was determined by radionuclide ventriculography and diastolic function by echocardiography. Autonomic function was assessed by 24-hour ECG registration for heart rate variability (HRV) analysis. Time-corrected QT (QTc) was assessed and N-terminal atrial natriuretic peptide (NT-ANP) and brain natriuretic peptide (BNP) were measured as biochemical markers of cardiac dysfunction.
Results: No patient developed overt congestive heart failure (CHF) and the mean LVEF declined from 0.61 at T0 to 0.54 at T3 (P =.001), resulting in an LVEF below 0.50 (range, 0.42 to 0.49) in 17% of the patients, whereas 28% had a decline of more than 0.10. Plasma NT-ANP levels increased gradually from 237 pmol/L at T0 to 347 pmol/L at T3 (P <.01), whereas plasma BNP levels increased from 2.9 pmol/L to 5.1 pmol/L (P =.04). Mean QTc increased from 406 msec at T0 to 423 msec at T3 (P <.01). No persistent alterations were found in diastolic function and HRV.
Conclusion: Relatively low doses of epirubicin in adjuvant chemotherapy for breast cancer results in mild subclinical myocardial damage demonstrated by a decline in LVEF, an increase in natriuretic peptide levels, and an increase in QTc, which may indicate a long-term risk of CHF.