Lack of Uniformity in Cardiac Assessment during Trastuzumab Therapy

Abstract

Adjuvant therapy with trastuzumab is standard in women with early stage HER-2-positive breast cancer. Following reports of left ventricular (LV) dysfunction with trastuzumab in metastatic disease, trials of adjuvant trastuzumab specified LV monitoring schedules. This study analyzes the pattern of cardiac testing and the incidence of heart failure (HF) in women treated with adjuvant trastuzumab in a real-world setting. De-identified medical and pharmacy claims data for women <65 years of age who began trastuzumab therapy between January 1, 2007 and December 31, 2007 were obtained from an integrated database at Medco Health Solutions, Inc. Patients receiving trastuzumab for ≥90 days were assessed for compliance with standard LV testing, defined as testing at baseline, at 4-month intervals, and at the end of trastuzumab therapy. Cardiac risk factors and HF were identified by ICD-9-CM diagnosis codes, by medical claims, and by pharmacy claims for drugs used to treat diabetes, hypercholesterolemia, or HF. A total of 631 women received trastuzumab ≥30 days, and 585 continued for ≥90 days (median duration 356 days [±1Q = 322-378]). Seventy nine patients had no LV tests. Ninety three were fully compliant with baseline, interval, and final testing. Seven women were identified as having new-onset HF. In this retrospective analysis, clinicians did not routinely follow LV testing protocols used in clinical trials or published recommendations. As breast cancer specific survival rates improve, the long-term contribution of cardiotoxic therapies to cardiac morbidity and mortality in survivors will gain attention. Early efforts to ensure compliance with testing could contribute to use of preventive therapies to mitigate future long-term consequences.

Utilization of cardiac monitoring tests in women with nonmetastatic breast cancer treated with trastuzumab

“…Using exploratory multivariable ana lysis, we found a positive relationship between cardiac monitoring and receipt of anthracycline-based chemotherapy. The anthracycline-related finding is not surprising, considering that anthracycline chemotherapy agents cause cardiac toxicity, and is consistent with the result of the study by Subar et al [13]. To our surprise, age, region and race were not associated with cardiac monitoring, possibly due to the small sample size.…”

“…Few other studies have evaluated the use of cardiac monitoring in routine clinical practice. Subar et al identified a 67% rate of baseline cardiac monitoring, an 88% rate of testing before or during therapy and a 16% rate of testing according to the standard monitoring schedule by using administrative data from 664 patients with nonmetastatic breast cancer treated with trastuzumab in 2007 [13]. While it is reassuring that our findings are similar, it is disappointing that both studies identify a subset of patients who do not have testing.…”

Adjuvant therapy for HER2+ breast cancer: practice, perception, and toxicity

“…Cardiotoxicity of trastuzumab-based therapies has been extensively scrutinized [3,5-7,16,15,18]. Although cardiotoxicity is important, our study signals a note of caution regarding the importance of other toxicities.…”

Early Cardiac Function Monitoring for Detection of Subclinical Doxorubicin Cardiotoxicity in Young Adult Patients with Breast Cancer

“…It appears that the monitoring guidelines for trastuzumab cardiotoxicity is more precise and easy-to-follow than anthracycline [26] and encourages clinician to follow the recommendations more carefully. However, there is a study which demonstrates that guidelines are still not strictly followed by clinicians in breast cancer patients treated with trastuzumab [27]. But in this study, the DOX plus TZ group underwent earlier and more frequent cardiac function monitoring during the chemotherapeutic period than DOX group and it could be the result from the precise monitoring guidelines of trastuzumab cardiotoxicity.…”