Cardiac safety of non-anthracycline trastuzumab-based therapy for HER2-positive breast cancer.

PURPOSE: Trastuzumab improves overall survival for women with HER2-positive breast cancer but is associated with cardiotoxicity, especially when administered after anthracyclines. Use of non-anthracycline trastuzumab-based regimens is rising, particularly for patients with low-risk disease or with multiple cardiovascular risk factors. We performed a single-center retrospective cohort study to assess the cardiac safety of trastuzumab without anthracyclines outside of a clinical trial setting.

METHODS: A retrospective chart review was conducted of patients with HER2-positive early-stage breast cancer receiving non-anthracycline trastuzumab-based therapy between January 2010 and June 2014. Cardiovascular risk factors, left ventricular ejection fraction (LVEF), and treatment interruption data were collected. The primary outcome was a cardiac event (CE), defined by New York Heart Association class III or IV heart failure or cardiac death. The secondary outcome was a significant asymptomatic decline of LVEF (>10% to <55% or >16% from baseline).

RESULTS: A total of 165 patients were identified with a median age of 59 years (range 32-85 years). Seventy (42%) had hypertension, 52 (32%) had hyperlipidemia, 29 (18%) had diabetes, and 5 (3%) had coronary artery disease. All patients had a LVEF >50% (median 67%; range 50-80%) at baseline. Two (1.2%) patients with multiple cardiovascular risk factors developed a CE. After discontinuation of trastuzumab, both patients had recovery of LVEF to >50% and resolution of heart failure symptoms. Ten (6.1%) patients developed significant asymptomatic LVEF decline during trastuzumab therapy.

CONCLUSIONS: The overall incidence of symptomatic heart failure and asymptomatic LVEF decline among patients receiving trastuzumab without anthracyclines remains low. These findings suggest that less intensive cardiac monitoring may be appropriate during trastuzumab therapy without anthracyclines.