Exposure to glucagon-like peptide-1 receptor agonists (GLP-1 RAs) may lower the risk of breast cancer incidence, according to findings from a retrospective analysis presented at the 2026 ASCO Annual Meeting (Abstract 10506). The findings were also published in JCO Oncology Practice.
“While our study was observational and does not definitively confirm an association between GLP-1 medications and reduced breast cancer incidence, it does add to the growing body of evidence suggesting that it’s worth investigating these weight-loss drugs as potential cancer prevention tools,” said Elizabeth McDonald, MD, PhD, a Professor of Radiology in the University of Pennsylvania Perelman School of Medicine and a practicing breast radiologist at Penn's Abramson Cancer.
Study Methods
Researchers conducted a retrospective cohort study to determine if GLP-1 RAs could impact breast cancer risk.
“GLP-1 medications are intriguing from a cancer research perspective because they weren’t designed for cancer therapy, but they do affect many different targets and pathways associated with cancer development, so we’re eager to study them in this context,” Dr. McDonald said.
They gathered electronic health records from 217,025 unique patients who had undergone breast imaging. They narrowed the cohort to women aged 45 to 80 years with a body mass index of 25 or above and a documented imaging outcome (n = 94,827).
GLP-1 RA use in the study consisted of a first prescription prior to the exam date. The researchers completed one-to-one, case-control matching using propensity scores to prevent potential confounding in assessments based on factors including race, ethnicity, age, and type 2 diabetes.
The primary outcome was breast cancer detection.
Key Findings
Overall, 2.4% of women in the cohort were diagnosed with breast cancer and 15.9% were exposed to a GLP-1 RA. Among the exposed group, 1.65% developed breast cancer.
Exposure to GLP-1 RAs was associated with a lower incidence of breast cancer (odds ratio [OR] = 0.630; 95% confidence interval [CI] = 0.552–0.720; P < .0001).
GLP-1 RA exposure prior to the exam date was also associated with a lower incidence of breast cancer by matched logistic regression (OR = 0.746; 95% CI = 0.632–0.880; P < .0005).
“Ultimately, we want to find better options to prevent breast cancer,” Dr. McDonald said. “It’s been encouraging to see the survival rates for breast cancer improve over recent decades, and we’d love to see the same gains in prevention.”
The researchers suggested that prospective studies are needed to further investigate the potential benefit of similar treatments for breast cancer prevention.
DISCLOSURES: The study was supported by the American College of Radiology Center for Research and Innovation, the Pennsylvania Breast Cancer Coalition, and the Abramson Cancer Center. For full disclosures of the study authors, visit asco.org.
