OBJECTIVES: Community health systems (CHS) in the US play a large role in the care of patients with cancer, with over 50% of patients with cancer cared for in CHS. The systemic treatments used among patients with advanced HER2+ breast cancer seen in CHS are not widely published. This analysis describes the systemic treatment utilization across a sample of CHS.

METHODS: A retrospective analysis was performed utilizing the Syapse Learning Health Network^TM (LHN), an electronic medical record (EMR) derived database that collects cancer care data from multiple care settings within CHS across 33 states, 450+ hospitals and from patients cared for by 1,900+ oncologists. Patients >18 yo, diagnosed at advanced stage breast cancer (IIIB+) from January 1, 2017 through December 9, 2021, were identified from the LHN using ICD-10 codes. Data utilized for this analysis included both structured data (EMR fields like sex and birth date) and unstructured data (e.g. physician notes) validated by Syapse’s Certified Tumor Registrars and then descriptively summarized.

RESULTS: 692 patients from the LHN with advanced HER2+ breast cancer (stage IIIB+) were included in the analysis. 521 patients (75%) received antineoplastic systemic treatment; in the 1L setting 80% received chemotherapy, 79% received targeted therapy and 18% received hormone therapy. Agents included: trastuzumab 70%; pertuzumab, 66%; docetaxel, 51%; carboplatin, 35%; paclitaxel, 20%; and cyclophosphamide, 12%.

CONCLUSIONS: Consistent with management guidelines, HER2+ patients with advanced breast cancer treated within CHS were most likely to receive 1L chemotherapy and HER2 targeted therapies, either trastuzumab or pertuzumab. Further analysis is necessary to better understand management decisions for this group of patients cared for within CHS