Incidence of Heart Failure or Cardiomyopathy After Adjuvant Trastuzumab Therapy for Breast Cancer

Study Questions:

What is the incidence of heart failure (HF) or cardiomyopathy (CM) after trastuzumab therapy for breast cancer?

Methods:

Surveillance, Epidemiology, and End Results (SEER)-Medicare is a database consisting of patient demographics and cancer characteristics from 16 tumor registries linked to Medicare claims that include date of service, diagnoses, and procedures (including biologic therapy and chemotherapy) from care billed by hospitals, outpatient facilities, and physicians. This database is a collaboration between the National Cancer Institute, SEER, and the Centers for Medicare and Medicaid Services. Data from 2000-2007 were used to identify women ages 67-94 years, with early-stage breast cancer. Incidence rates for two outcomes, HF and CM, were calculated for specific treatment groups. The groups examined were trastuzumab (with or without nonanthracycline chemotherapy), anthracycline plus trastuzumab, anthracycline (without trastuzumab and with or without nonanthracycline chemotherapy), other nonanthracycline chemotherapy, or no adjuvant chemotherapy or trastuzumab therapy. Outcomes were identified through Medicare claims data. Models were adjusted for sociodemographic factors, cancer characteristics, and cardiovascular conditions.

Results:

A total of 45,537 women (mean age 76.2 years) with early-stage breast cancer were included in this analysis. Overall, 431 (1.0%) received trastuzumab, 431 (0.9%) received anthracycline plus trastuzumab, 5,257 (11.5%) received anthracycline-based chemotherapy, 2,712 (5.9%) received other (nonanthracycline) chemotherapy, and 36,700 (80.6%) received no adjuvant chemotherapy or trastuzumab. Adjusted 3-year HF or CM incidence rates were higher for patients receiving trastuzumab (32.1 per 100 patients) and anthracycline plus trastuzumab (41.9 per 100 patients) compared with no adjuvant therapy (18.1 per 100 patients, p < 0.001). Adding trastuzumab to anthracycline therapy added 12.1, 17.9, and 21.7 HF or CM events per 100 patients over 1, 2, and 3 years of follow-up, respectively.

Conclusions:

The investigators concluded that HF and CM are common complications after trastuzumab therapy among older women being treated for breast cancer.

Perspective:

Rates observed in the analysis of Medicare data were higher than those observed in clinical trials. These data suggest the need to identify which women are at particular risk for cardiac complications during treatment for breast cancer.

Clinical Topics: Dyslipidemia, Heart Failure and Cardiomyopathies, Lipid Metabolism, Novel Agents, Acute Heart Failure

Keywords: Antibodies, Monoclonal, Humanized, Follow-Up Studies, Biological Therapy, Lipids, Breast Neoplasms, Chemotherapy, Adjuvant, Centers for Medicare and Medicaid Services (U.S.), Anthracyclines, Neoplasm Recurrence, Local, Combined Modality Therapy, Registries, Incidence, Outpatients, Sodium, Dietary, Cardiomyopathies, Heart Failure, United States


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