Abstract 18979: Early Termination of Adjuvant Trastuzumab Associated with Cardiovascular Events in Older Women with Breast Cancer
Background: Biologic therapies for breast cancer such as trastuzumab, (i.e. Herceptin© [H]) increase risk of cardiovascular (CV) events such as heart failure (HF) in clinical trials. However, it is unknown how often H therapy is terminated early (i.e. < 1yr), and which CV complications are associated with early termination.
Methods: Using Medicare data linked with SEER cancer registry data from 2000 through 2007, we identified women age 67-94 with stage I-III breast cancer who started H within 90 days of completing adjuvant chemotherapy. Completion of H was defined as >=9 months of continuous H treatments with no delay between H treatments >3 months. We assessed factors contributing to completion of H including age, race, cancer characteristics, and comorbidities. CV events occurring +/- 3 months from last H treatment were ascertained from billing claims.
Results: The sample included 294 older women (mean age 71.5 years) without CV events within the year prior to initiation of H. Approximately 79.3% (233) patients completed at least 9 months of H. Early termination of H was significantly associated with any CV complications (27.9% v 8.6%, p<.001), particularly HF or cardiomyopathy (6.6% v 0.4%, p<.001), p=.02) and atrial fibrillation [AF] (8.2% v 2.1%, p=0.02)
Conclusion: Early termination of H is common among older women, and associated with higher rates of cardiovascular events. Preventing CV complications such as AF may improve survival in patients with breast cancer by increasing the likelihood of receiving the recommended course of H therapy. Funding(This research has received full or partial funding support from the American Heart Association)
- © 2012 by American Heart Association, Inc.