GLP-1 Drugs May Lower Breast Cancer Risk, New Study Finds

A large retrospective analysis involving over 110,000 women aged 45 to 80 suggests that GLP-1 medications, commonly used to treat obesity and type 2 diabetes, may be associated with a significantly lower risk of developing breast cancer. The findings, presented at the American Society of Clinical Oncology (ASCO) annual meeting and published in JCO Oncology Practice, indicate a potential protective effect.

The study examined the medical records of 111,646 women with a body mass index (BMI) over 25 who underwent mammography screening between January 2022 and June 2025. Of these, 15,264 women (13.7%) had been prescribed GLP-1 medications, while the remaining 96,382 (86.3%) had not. The analysis, conducted both on the entire cohort and a matched subgroup, consistently showed a reduced incidence of breast cancer among GLP-1 users.

Specifically, the overall probability of breast cancer diagnosis was 35.1% lower in the total sample, and 30.5% lower in the matched subgroup. Researchers hypothesize that the drugs' role in weight management, a known factor in breast cancer prevention, and their potential to reduce chronic low-grade inflammation could contribute to this observed effect. However, the study did not account for specific drug types, duration of use, genetic risk factors, or disease stage at diagnosis.

Dr. Elizabeth McDonald, Professor of Radiology at the Perelman School of Medicine, University of Pennsylvania, emphasized that this observational study does not prove causation. Nevertheless, she noted that it adds to a growing body of evidence suggesting GLP-1 weight-loss drugs could become new tools for cancer prevention. Scientists are now planning a multi-center clinical trial to definitively investigate whether these medications can reduce breast cancer incidence in high-risk women.

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This analysis is an observational study and does not prove a causal relationship. Nevertheless, it strengthens the growing body of evidence suggesting that GLP-1 weight-loss drugs could become new tools for cancer prevention.