Early detection of epirubicin-induced cardiotoxicity in patients with breast cancer

Background: Epirubicin is a cytotoxic drug, widely used in patients with breast cancer, but its application is limited by its cardiotoxicity. Assessment of left ventricular (LV) ejection fraction (EF) is performed to demonstrate cardiac dysfunction. Because normal EF can mask LV impairment, the aim of this study was to evaluate whether deformation and rotation assessed using speckle-tracking echocardiography represent better markers of early epirubicin-induced cardiotoxicity.

Methods: Forty women with breast cancer (mean age, 51 ± 8 years), scheduled to be treated with epirubicin-based chemotherapy, were prospectively enrolled. All patients underwent conventional echocardiography, tissue velocity imaging, and speckle-tracking echocardiography to evaluate LV geometry and EF, S', deformation (longitudinal, circumferential, and radial strain and strain rate), and rotation. Patients were reevaluated after the third and sixth cycles of epirubicin (mean cumulative dose, 268 ± 22 g/m(2)).

Results: After the sixth cycle of treatment, 14 patients (35%) had developed epirubicin-induced cardiotoxicity (a decrease in EF of ≥10% to an EF of <55%; group I), and 26 patients (65%) did not fulfill the criteria for cardiotoxicity (group II). In the entire study population, after the third cycle of epirubicin, there were reductions in diastolic and longitudinal function, but patients in group I had significantly lower S', longitudinal strain, and longitudinal strain rate than those in group II. Although after the third cycle of treatment, radial and circumferential deformation and rotation remained unchanged, these parameters showed significant reductions after the sixth cycle of epirubicin. A decrease in longitudinal strain after the third cycle of epirubicin was the best independent and accurate predictor of cardiotoxicity after the completion of treatment.

Conclusions: Assessment of myocardial longitudinal deformation detects subclinical LV dysfunction and can predict further changes in EF and therefore can be used to monitor epirubicin-induced cardiotoxicity.