Abstract 9317: Impact of Trastuzumab-Induced Cardiotoxicity and Subsequent Trastuzumab Interruption on Breast Cancer Outcome
Background: Trastuzumab (T) improves disease free and overall survival among pts with HER2 (+) breast cancer (BCA); however this benefit is attenuated by the risk of trastuzumab-induced cardiotoxicity (TIC). Current guidelines recommend interruption of T for CHF or a significant reduction in LVEF, but the impact of this practice on BCA outcomes is unknown.
Methods: All patients with HER2 (+) BCA receiving adjuvant T with chemotherapy in clinical practice at a single cancer center between January 2005 and June 2010 were studied. Tumor characteristics, cardiac risk factors, LVEF, BCA chemotherapy, and BCA outcomes were obtained from the medical record. The log rank test and Cox proportional model were used to evaluate the association between these variables and time to BCA recurrence.
Results: Overall, 546 pts with HER2 (+) BCA treated with T were studied; 448 (82%) pts were treated with anthracyclines prior to T. Mean age was 51 yrs (range 26-81); mean follow-up was 4.4 yrs (range 0.6-7.6). T was interrupted for > 1 cycle (> 6 weeks) in 83 (15%) pts. TIC was the reason for interruption in 54 (9.9%) pts; 18 (3.3%) had symptoms of CHF with a decline in LVEF, while 36 (6.6%) had an asymptomatic decline in LVEF. Other reasons for interruption included non-cardiac adverse events (n=11), BCA progression (n=7), and pt request (n=7). Cumulative dose of T was lower among pts with interruption (median 76 vs. 106 mg/kg, p < 0.0001). Early recurrence of BCA was associated with number of positive lymph nodes (p<0.0001), negative progesterone receptor status (p=0.005), interruption of T > 1 cycle for any cause (p=0.006), and interruption of T > 1 cycle due to TIC (p=0.049, Table).
Conclusions: TIC was the most common reason for interruption of T and was significantly associated with BCA recurrence. These results suggest that coordination of care between cardiologists and oncologists to limit T interruptions while effectively treating cardiotoxicity has the potential to improve outcomes in women with BCA.
- © 2013 by American Heart Association, Inc.