Bold claim: GLP-1 use among breast cancer patients might be more common than you think, and it could be quietly reshaping outcomes beyond weight management. And this is the part most people miss: the real-world patterns and potential links to tumor biology are just beginning to come into focus.
SABCS 2025 highlighted a large, real-world look at glucagon-like peptide 1 (GLP-1) receptor agonists in breast cancer care. Obesity is a recognized driver of breast cancer risk, progression, and recurrence, and GLP-1 agents have become trusted tools for weight control. The study explored whether GLP-1 therapy in breast cancer patients aligns with clinical outcomes, social determinants of health (SDOH), and circulating tumor DNA (ctDNA) markers.
Study scope and methods
Researchers analyzed electronic health records from 708,406 individuals diagnosed with breast cancer between January 2011 and February 2025. They used artificial intelligence-assisted data extraction to identify documented GLP-1 use and to examine its relationship with clinical features, sociodemographic factors, ctDNA testing, and ctDNA positivity.
Who’s using GLP-1—and why
Overall, 7.6% of patients had documented GLP-1 therapy. The predominant reasons included diabetes management, weight loss, cardiovascular concerns, and obstructive sleep apnea. GLP-1 use was more common in patients with a body mass index (BMI) of 30 or higher, among non-Latinx Black patients, telemedicine users, and individuals living in rural areas. Conversely, usage was lower among those over 75 years old, patients with advanced disease (stage IV), tumors that are HR-/HER2-, Latinx and Asian patients, people with limited English proficiency, and patients treated at community medical centers rather than academic institutions.
Connections to tumor activity
A notable finding was that GLP-1 users were more likely to have ctDNA testing performed (2.8% vs. 1.5%). Among those tested, GLP-1 users showed a lower ctDNA positivity rate (25.8% vs. 31.6%). While this is a correlation and not proof of causation, the association hints at a possible link between GLP-1 therapy and reduced circulating tumor activity, suggesting these medications might offer benefits in oncology care that go beyond weight management.
Implications and areas for future work
The study emphasizes how a patient’s clinical profile, social context, and health system factors shape GLP-1 use and reveals clear disparities in access to such therapies. The authors call for prospective research to determine whether GLP-1 medications directly influence breast cancer outcomes and to ensure equitable access to supportive treatments across diverse populations.
In many ways, this analysis stands as one of the largest real-world investigations into GLP-1 use within breast cancer care. It opens new questions about potential benefits and lays groundwork for future studies to validate findings, optimize patient selection, and explore integration into standard oncology practice.
Reference
Ryals CA et al. Real-world glucagon-like peptide 1 use and association with clinical characteristics, social determinants, and circulating tumor DNA positivity in patients with breast cancer. Abstract PD8-07-02. SABCS 2025; 9-12 December.
Author note
This article is shared under the Creative Commons Attribution-Non Commercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/).
