GLP-1 medicines are best known for treating type 2 diabetes and helping with weight loss. Now, researchers are studying whether these medications may have other health effects, including a possible link to lower breast cancer risk.
A new study looked at women who had breast imaging and found that those prescribed GLP-1 medicines had a lower rate of breast cancer than those who were not prescribed these medicines. The results are promising, but this was not a controlled trial, but only observed people over time. That means it can show a link, but it cannot prove that GLP-1 medicines directly prevent breast cancer.
What did the researchers study?
The researchers wanted to know whether GLP-1 medicines were associated with breast cancer incidence in women who were eligible for breast cancer screening and had overweight or obesity.
The study used electronic health records from a large health system connected with the University of Pennsylvania. The records came from academic and community sites in Delaware Valley, Central Jersey, and South Central Pennsylvania. The study period was January 1, 2022, through June 30, 2025.
Researchers first identified 217,624 women who had breast imaging. They then focused on women ages 45 to 80 with a BMI of 25 or higher and a documented imaging result. The final study group included 111,646 women. The median age was 61.
The main outcome was whether breast cancer was detected during the study period. GLP-1 use was defined as having a first prescription before the breast imaging exam date.
What were the main results?
Of the 111,646 women in the study, 15,264 had GLP-1 exposure, and 96,382 did not. During the study period, 2,628 women were diagnosed with breast cancer.
Among women exposed to GLP-1 medicines, 247 out of 15,264 developed breast cancer. That equals 1.62%. Among women without GLP-1 exposure, 2,381 out of 96,382 developed breast cancer. That equals about 2.47%.
The researchers also used a matching method to make the two groups more similar. They matched patients based on age, race, ethnicity, BMI, breast density, and history of type 2 diabetes. This helped reduce differences that could affect the results.
In the matched analysis, there were 30,528 total observations. Breast cancer was found in 247 women with GLP-1 exposure and 353 women without GLP-1 exposure. Overall, GLP-1 exposure was associated with about a 30% lower odds of breast cancer. The absolute risk reduction was 0.69%.
Why is this finding promising?
This finding is promising because GLP-1 medicines may have benefits beyond blood sugar control and weight loss. Extra body weight is linked with breast cancer risk, and GLP-1 medicines can support weight loss and improve metabolic health.
The article also notes that GLP-1 medicines may reduce inflammation. Since inflammation can play a role in cancer development, researchers are interested in whether these medications could have cancer-preventive effects.
This study is also useful because it focused on women eligible for breast cancer screening who were overweight or obese. It included a large number of women and used real-world health records, which makes the findings helpful for planning future research.
What are the limits of the study?
The results are just preliminary and they should be understood carefully. This was not a randomized clinical trial. It was an observational study using existing health records, so it cannot prove cause and effect.
The study also did not measure exactly how long each woman used a GLP-1 medicine or what dose she took. Patients may have used different GLP-1 drugs at different doses. Some women listed as not exposed may also have received these medicines outside the health system.
These limits matter. The study shows an important association, but more research is needed before GLP-1 medicines can be considered for breast cancer prevention.
How can I apply this information?
This research suggests that GLP-1 medicines may be linked with a lower rate of breast cancer in women ages 45 to 80 with overweight or obesity who underwent breast imaging.
At the same time, this is still research and GLP1 medications are not FDA approved for this indication. It is very important to note that people should not start or stop a GLP-1 medicine based only on this study rather only as prescribed by your health care provider for the indications that are approved. These medications can have side effects, including nausea, vomiting, diarrhea, constipation, and gallbladder-related problems.
The main conclusion is that it is promising that GLP-1 treatment was associated with lower breast cancer incidence, even after accounting for age, race, ethnicity, BMI, breast density, and diabetes. The authors state that future prospective trials are needed to study whether GLP-1 medicines could help prevent breast cancer.
Source:
McDonald ES, Gillis LB, Gabriel P, Xapakdy K, Young A, Doucette A, Schnall MD, Buse JB, Pisano ED. GLP-1 agonists are associated with a significant reduction in breast cancer incidence in women. JCO Oncol Pract. 2026 Jun 2. doi:10.1200/OP-26-00485R1. Accessed June 4, 2026. Available from: https://doi.org/10.1200/OP-26-00485R1
