Trastuzumab-Induced Cardiomyopathy: Incidence and Associated Risk Factors in an Inner-City Population

Background: Although it is known that trastuzumab causes cardiotoxicity, its extent and reversibility are still in question. Earlier studies have not evaluated consecutive patients with reproducible nuclear ventriculography. Objective: We sought to evaluate the baseline characteristics which predispose patients to increased risk of trastuzumab cardiotoxicity and to determine the natural history of the cardiotoxicity. Methods and Results: Left ventricular ejection fraction (LVEF) was measured in 76 women aged 36-73 years who had been treated with trastuzumab at the University of Maryland Greenebaum Cancer Center. LVEF was determined at baseline and then 3, 6, 9, and 12 months after treatment initiation. Cardiotoxicity was defined as >= 16% decrease in LVEF or >= 10% decrease in LVEF to <50%. There were no differences in comorbidities, earlier treatment, or demographics between patients with and without trastuzumab-induced cardiomyopathy except that African Americans were more likely to develop decreased LVEF (P <.05). Twenty-one patients (28%) met criteria for cardiotoxicity. Four of those patients were continued on trastuzumab and 17 patients had therapy withheld at some point. Only 1 patient developed symptomatic heart failure requiring inpatient hospitalization. LVEF improved in most patients regardless of whether or not trastuzumab was continued. Conclusions: Decreased LVEF while undergoing trastuzumab therapy occurs frequently and is usually reversible. African Americans had a higher risk of developing decreased LVEF. These findings raise clinically important questions as to whether it is necessary to discontinue trastuzumab for asymptomatic decrease. in LVEF and whether African Americans are more predisposed to a decrease in LVEF while receiving trastuzumab. Further studies carefully assessing LVEF should address these hypotheses.