Abstract P4-14-09: Cardiac safety of trastuzumab without an anthracycline in patients with HER2-positive early stage breast cancer: A single center experience

Abstract

Abstract Background: Trastuzumab (H) improves disease-free survival and overall survival in HER2+ early breast cancer (EBC) but is associated with risk of treatment-induced cardiotoxicity especially when administered after an anthracycline. We performed a single center retrospective study to assess the cardiac safety of adjuvant trastuzumab therapy without anthracyclines in a real-world clinical setting. Methods: Patients (pts) with HER2+ early breast cancer (EBC) who received H without anthracycline-based chemotherapy between January 2010 and June 2014 were studied. Patients enrolled in a clinical trial were excluded. Tumor characteristics, chemotherapy regimen, cardiovascular risk factors, left ventricular ejection fraction (LVEF), and treatment interruption data were collected. A cardiac event (C.E.) was defined as New York Heart Association class III or IV heart failure with LVEF decline of > 10% to < 55% or possible/probable cardiac death, as previously defined by the NSABP B-31 trial. Results: In total, 174 pts with HER2+ EBC treated with H-based therapy without anthracyclines were identified. Median age was 59 years (range, 32 to 85 years), 72 (41%) had hypertension, 55 (32%) had hyperlipidemia, 29 (16%) had diabetes, and 5 (3%) had coronary artery disease. At baseline, all pts had a LVEF > 50% (median, 66%; range, 50% to 81%). Two (1.1%) pts developed a C.E. Both pts had risks factors for C.E. (1 - age > 60 years, hypertension, and prior history of anthracycline exposure; 1- age > 60 years, hypertension, hyperlipidemia, and baseline LVEF of 50-55%). After discontinuation of H, both patients had recovery of LVEF to > 50% and resolution of heart failure symptoms. Twelve (6.9%) pts developed asymptomatic LVEF decline of > 10% points to < 55% during H therapy. Of the 14 patients who developed cardiotoxicity, H was prematurely interrupted or discontinued in 8 patients. Conclusion: In our single center experience of patients being treated off study, the incidence of C.E.s and asymptomatic LVEF decline during H therapy without an anthracycline was 1.1% and 6.9%, respectively. These appeared higher than events reported in clinical trials possibly due to the inclusion of an older group of women with a higher prevalence of cardiovascular risk factors. Overall, the incidence of symptomatic heart failure is low for H without an anthracycline even in this older group. Citation Format: Mukku RB, Verma S, Liu J, Steingart R, Hudis C, Yu AF, Dang C. Cardiac safety of trastuzumab without an anthracycline in patients with HER2-positive early stage breast cancer: A single center experience. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-09.