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 profile of patients with HER2- breast cancer seen in CHS within the US is not widely published. This analysis describes the demographic and diagnostic staging characteristics of patients with HER2- breast cancer treated 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 cared for by 1,900+ community oncologists. Patients aged >18 yo at breast cancer diagnosis from January 1, 2010 - December 3, 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: 55,911 patients from the Syapse LHN were included in this analysis. Patient demographics included: median age of 64 yo at diagnosis with 81% being >50 yo; 99% female; with race including 80% White, 14% Black, 3% Asian, 3% other; 5% of Hispanic/Latino ethnicity. 49,503 patients (89%) had stage at diagnosis available; 91% diagnosed in the early stages (0 - IIIA) and 9% diagnosed in the advanced stages (IIIB+) of breast cancer.

CONCLUSIONS: Patients with HER2- breast cancer treated in community health systems within the LHN tend to be older, menopausal or post menopausal based on age, and with most diagnosed at early stage of disease. Additional analysis is planned to provide further insight into clinical characteristics and treatment patterns of patients with HER2- breast cancer treated within CHS.