GLP-1 drugs linked to about 30% lower breast cancer risk in large Penn Medicine study
A large observational study from Penn Medicine, presented at the 2026 ASCO meeting, found that women on GLP-1 medications were about 30 percent less likely to develop breast cancer. Researchers tracked nearly 112,000 women aged 45 to 80. The study cannot prove cause, and a clinic
Researchers at the University of Pennsylvania's Perelman School of Medicine reviewed records of nearly 112,000 women aged 45 to 80 who had breast imaging at Penn Medicine between 2022 and 2025. Women with excess weight taking GLP-1 medications, the class behind Ozempic and Wegovy, were about 30 percent less likely to develop breast cancer. The findings were presented at the 2026 American Society of Clinical Oncology meeting. The study is observational and cannot prove the drugs caused the drop; possible reasons include weight loss, lower inflammation, and metabolic effects. A multisite clinical trial is now being planned. Sources: Penn Medicine, ASCO 2026, US News, Healthline.