Decline in Left Ventricular Ejection Fraction Following Anthracyclines Predicts Trastuzumab Cardiotoxicity

Objectives: The aim of CATS (Cardiotoxicity of Adjuvant Trastuzumab Study) was to prospectively assess clinical, biochemical, and genomic predictors of trastuzumab-related cardiotoxicity (TRC).

Background: Cardiac dysfunction is a common adverse effect of trastuzumab. Studies to identify predictive biomarkers for TRC have enrolled heterogeneous populations and yielded mixed results.

Methods: A total of 222 patients with early-stage human epidermal growth factor receptor 2-positive breast cancer scheduled to receive adjuvant anthracyclines followed by 12 months of trastuzumab were prospectively recruited from 17 centers. Left ventricular ejection fraction (LVEF), troponin T, and N-terminal prohormone of brain natriuretic peptide were measured at baseline, post-anthracycline, and every 3 months during trastuzumab. Germline single-nucleotide polymorphisms in ERBB2, FCGR2A, and FCGR3A were analyzed. TRC was defined as symptomatic heart failure; cardiac death, arrhythmia, or infarction; a decrease in LVEF of >15% from baseline; or a decrease in LVEF of >10% to <50%.

Results: TRC occurred in 18 of 217 subjects (8.3%). Lower pre-anthracycline LVEF and greater interval decline in LVEF from pre- to post-anthracycline were each associated with TRC on multivariate analyses (odds ratio: 3.9 [p = 0.0001] and 7.9 [p < 0.0001] for a 5% absolute change in LVEF). Higher post-anthracycline N-terminal prohormone of brain natriuretic peptide level was associated with TRC on univariate but not multivariate analyses. There were no associations between troponin T or ERBB2/FGCR polymorphisms and TRC. Baseline LVEF and LVEF change post-anthracycline were used to generate a "low-risk TRC score" to identify patients with low TRC incidence.

Conclusions: Low baseline LVEF and greater LVEF decline post-anthracycline were both independent predictors of TRC. The other biomarkers did not further improve the ability to predict TRC. (Cardiotoxicity of Adjuvant Trastuzumab [CATS]; NCT00858039).