GLP-1 Drugs Linked to 30 Percent Lower Breast Cancer Risk in Large Study
A study presented at the 2026 ASCO Annual Meeting found that women taking GLP-1 medications had about 30 percent lower odds of developing breast cancer. Researchers analyzed records from more than 111,000 women and say a prospective clinical trial is now being planned.
Women taking GLP-1 receptor agonist medications had roughly 30 percent lower odds of developing breast cancer compared to women not taking the drugs, according to a study presented at the 2026 American Society of Clinical Oncology Annual Meeting.
Researchers at the University of Pennsylvania's Perelman School of Medicine analyzed electronic health records from 111,646 women between the ages of 45 and 80, all with a body mass index of 25 or higher. Of those, 15,264 had documented prescriptions for GLP-1 medications such as Ozempic or Wegovy.
In a matched cohort analysis pairing GLP-1 users one-to-one with non-users based on age, race, BMI, and other factors, the GLP-1 group showed a 30.5 percent lower risk of breast cancer. The absolute difference amounted to roughly seven fewer breast cancer diagnoses per 1,000 women.
Lead researcher Dr. Elizabeth McDonald said the findings are promising but require confirmation. The study was observational and did not account for specific drug types, dosages, or duration of use.
Researchers believe GLP-1 drugs may reduce breast cancer risk by lowering systemic inflammation and improving metabolic function. Some studies also suggest the drugs may have epigenetic effects that inhibit tumor growth.
McDonald and her team are now working to launch a multisite, prospective clinical trial to test whether GLP-1 medications can serve as a preventive strategy for breast cancer, particularly in high-risk populations. The findings were also published in JCO Oncology Practice.
