Current guidelines recommend cardiac function monitoring every 3 months in patients receiving trastuzumab, however evidences for optimal cardiac surveillance strategy are lacking. The aim of this study is to identify risk factors and to characterize clinical patterns of trastuzumab related cardiac dysfunction(TRCD) within 1 year of treatment in patients with breast cancer.
We identified and reviewed consecutive patients with breast cancer received trastuzumab and adequate cardiac monitoring (baseline and subsequent cardiac echocardiogram at least every 4 months) between Jan 2010 - Apr 2017 at a single center. TRCD were defined as an absolte decrease of ejection fraction(EF) ≥15% or ≥ 10% to below the lower limit of normal.
Among 364 patients(median age 51 years), TRCD was developed in 33 patients (9.3%). Median time from trastuzumab to TRCD was 6.3 months(range 2.6-12.3). Incidence of TRCD was significantly higher in patients with prior anthracycline (12.1% vs. 5.1%, p = 0.026). In 20 out of 33 patients (60.6%), TRCD was diagnosed within the first 6 months of trastuzumab. Earlier TRCD was significantly associated with prior anthracycline (72% vs. 25%, p = 0.035). Among the patients with later TRCD development after 9 months of trastuzumab (n = 13), absolute EF decrease >5% in the first 6 months preceded in 10 patients (76.9%). Incidence of later TRCD was significantly lower in patients whose absolute EF decrease < =5% in the first 6 months (2.1%) than in whom with more than 5% of absolute EF decrease (11.8%).
TRCD development occurs earlier within the first 6 months of trastuzumab in patients with prior anthracycline use. The degree of absolute EF decrease in the first 6 months can predict later development of TRCD. Therefore, cardiac monitoring for the first 6 months of trastuzumab treatment should not be missed, especially in whom with prior exposure to anthracyclie. Adaptive less frequent cardiac surveillance strategy after 6 months may be considered in patients without significant EF change.
Clinical trial identification
Legal entity responsible for the study
Hee Kyung Ahn.
Has not received any funding.
All authors have declared no conflicts of interest.