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.