P2-18-05: Cardiotoxicity Risks of Adjuvant Trastuzumab in Asian Breast Cancer Patients.

Abstract

Abstract Background: Adjuvant trastuzumab (T)-based chemotherapy reduces relapse and improves overall survival in early breast cancer. However, T-associated cardiotoxicity potentially limits its use. Our study aims to report the incidence, severity and reversibility of cardiotoxicity amongst Asian breast cancer patients. Methods: This is a retrospective review of patients who have received adjuvant T from June 2005 to March 2011 at our centre. CT was defined as a drop in left ventricular ejection fraction (LVEF) to less than 50% and / or reduction of ≥ 10% of baseline. Cardiovascular (CVS) risk factors were defined as having at least one of the following factors: family or previous history of CAD, hypertension, diabetes mellitus, hyperlipidemia and smoking. One-way repeated measures ANOVA was used to evaluate the mean LVEF change and Chi-square test to evaluate the association of demographics and CT. Results: A total of 314 female patients were reviewed. CT was reported in 124 (39.5%), of whom 96 had asymptomatic decline in LVEF and 28 were symptomatic. T was withheld (n=53) due to asymptomatic decline in LVEF (n=40), symptomatic heart failure (n=3) and both (n=10). Forty-three patients with resolution of CHF (n=11) or LVEF recovery (n=32) were rechallenged. Cardiotoxicity recurred in 14 - asymptomatic decline in LVEF (n=10), recurrent CHF (n=1) and both (n=3). Overall, there were no cardiac-related deaths. Factors that predicted for CT included low normal pre-trastuzumab LVEF (<60%) (p=0.01), prior anthracyclines (p=0.011), decline in LVEF pre-anthracycline and before T (p=0.022) and BMI ≥ 23kg/m2 (p=0.018). Three-monthly LVEF showed statistically significant decline against baseline over the time points (p=0.005). As expected, the decline in LVEF demonstrated significant interaction with CT groups and non CT group (p<0.001). Conclusions: A higher incidence of CT (39.5%) was observed among Asian breast cancer patients compared to previously reported in Caucasians (24%). Although 77.4% of patients presented with asymptomatic decline in LVEF, approximately one-third of patients experienced recurrent CT upon rechallenge. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-18-05.