Health AI Central
Peer-Reviewed Publication
Breast Cancer Res Treat2026;219(2)September 9, 2026Journal Article

Real-world estrogen receptor alpha 1 (ESR1) testing patterns and results for ER+/HER2- metastatic breast cancer in the United States, 2018-2024.

Jane Meisel1, Tim Pham2, Clara Chen2, Ayush Kris3, James Roose4
1Department of Hematology and Medical Oncology, Emory Winship Cancer Institute, Emory University, Atlanta, GA, USA.
2AstraZeneca, Gaithersburg, MD, USA.
3Flatiron Health, New York, NY, USA.
4Flatiron Health, New York, NY, USA. james.roose@flatiron.com.
PubMed DOI

Abstract

PURPOSE: To understand historical and recent ESR1 testing rates, and when ESR1 mutations emerge during first-line (1 L) treatment. METHODS: This retrospective, observational cohort study used the Flatiron Health Research Database (FHRD) and the Flatiron Health-Foundation Medicine metastatic breast cancer (mBC) Clinico-Genomic Database (CGDB). Adult patients with a confirmed diagnosis of hormone r…

Create a free account to keep reading

Free members get 10 full research views every month across publications, clinical trials, FDA clearances, adverse events, and NIH grants. No credit card required.

Create Free AccountSign In

Want unlimited research access? See Pro plans

Data Accuracy Notice: Research intelligence on Health AI Central is aggregated from public sources (PubMed, ClinicalTrials.gov, FDA, NIH, CMS, and others) and refreshed nightly. Classifications and derived metrics are produced by automated methods described in our Methodology. We recommend verifying critical data points against the primary sources before making decisions.