Abstract PS10-20: Neoadjuvant (neoadj) and adjuvant (adj) treatment patterns in HER2-positive early breast cancer (EBC): Analysis of US real-world oncology data

Abstract

OBJECTIVES Over the last decade, new treatment options have transformed the standard of care for patients (pts) with HER2-positive EBC and the treatment landscape continues to evolve. The primary objectives of our study were (1) to describe and compare the demographic and clinical characteristics of pts with HER2-positive EBC who received neoadj or adj treatment, (2) to describe the common neoadj and adj regimens according to hormone receptor (HR) status, and (3) to describe trends in neoadj treatment use from 2011 to 2019 in a US real-world setting. METHODS Unstructured and structured electronic health record-derived data were analyzed from the US Flatiron Health de-identified database (2011-2020), a longitudinal database of >2.4 million pts with cancer in >280 clinics, largely from community-based practices. Eligible pts had HER2-positive EBC (diagnosis: Jan 1, 2011-Jul 31, 2019; follow-up: until Feb 29, 2020). Systemic or oral anti-neoplastic treatments with initiation either prior to (neoadj) or within 6 months (adj) of the first primary surgery date were included. Adj treatment also required at least 6 months of follow-up and was captured for up to 1 year after initiation of adj therapy. RESULTS Pts with HER2-positive EBC treated in the neoadj setting, versus those in the adj setting alone, were more likely to be younger, pre-menopausal, have HR-negative disease, clinical stage II or III stage disease (refer to footnote in Table 1), have received treatment at an academic center, and were ~2 times as likely to have bilateral mastectomies (Table 1). Conversely, race/ethnicity as well as tumor grade, histology and laterality did not differ by neoadj versus adj treatment. The most common therapies are presented in Table 1. There was an upward trend in the annual percentage of pts diagnosed with HER2-positive EBC who initiated neoadj treatment starting in 2011 ( CONCLUSIONS Neoadj therapy use has increased, which is in line with changes in the standard anti-HER2 therapies that have occurred since 2013. Despite considerable variation, neoadj pts are mostly treated with dual HER2 blockade and chemotherapy, with a preference for taxane-based regimens. Citation Format: Preet K. Dhillon, Carlos Flores, Thibaut Sanglier, Vincent Antao, David Tesarowski, Anita Fung, Devin Incerti, Eleonora Restuccia, Patricia Luhn. Neoadjuvant (neoadj) and adjuvant (adj) treatment patterns in HER2-positive early breast cancer (EBC): Analysis of US real-world oncology data [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-20.