Can GLP-1 Medications Reduce Breast Cancer Risk?
Excess weight, especially after menopause, is a major modifiable risk factor for breast cancer. Glucagon-like peptide-1 (GLP-1) drugs are very effective for weight loss and improving metabolic health, and therefore may reduce risk for breast cancer.
In a retrospective study from the University of Pennsylvania Health System, investigators evaluated electronic health records from women aged 45–80 years who were overweight (BMI 25-<30) or obese (BMI ≥30). The authors compared breast cancer incidence among 15,264 women with prior GLP-1 exposure1 to the same number of women without exposure, with matching for age, BMI, breast density, race, ethnicity, and history of diabetes.
Key Findings
- Breast cancer incidence was lower in women who had used GLP-1 drugs than in women who had not.2
- After matching women for age, BMI, breast density, race, ethnicity, and diabetes history, GLP-1 use remained associated with reduced rate of breast cancer. Women using GLP-1 medications had an approximately 30% reduced risk for breast cancer.3
- The association between GLP-1 use and lower breast cancer incidence was independent of breast density.3
- Reduced risk for breast cancer was similar in women both with and without diabetes and among both Black and White women.4
This study did not examine duration of GLP-1 use, dosage, nor time from starting GLP-1 use to the breast imaging. The authors did not require any specific follow-up period to ascertain breast cancer diagnosis nor linkage to a tumor registry. Women in the control group may have been using non-prescription GLP-1s (which would have diluted the observed effect).
There is need for long-term prospective trials of GLP-1 drugs to confirm efficacy in breast cancer
prevention. With weight loss, breast density can appear to increase, and this could mask detection of breast cancer on mammography and may also prompt additional false alarms for findings that are not cancer. This study did not evaluate serial mammograms over time for changes in breast density associated with GLP-1 use and did not quantify weight loss.
Detailed Results
1From January 1, 2022, to June 30, 2025, GLP-1 exposure was defined as first prescription prior to the breast imaging examination with documented outcome from the imaging; In the total study population of 111,646 women, 15,264 women had GLP-1 exposure and 96,382 did not. The analysis was based on 15,264 women with and 15,264 matched women without GLP-1 exposure. Overall, 4059 (13.3%) women had breast ultrasound or MRI and not mammography for this analysis.
2In the full study population, breast cancer was diagnosed in 1.62% (247/15,264) of women with GLP-1 exposure compared with 2.47% (2,381/96,382) of women without exposure, corresponding to an odds ratio (OR) of 0.649 (95% CI, 0.569–0.741; P<0.0001).
3After propensity-score matching for age, BMI, breast density, race, ethnicity, and diabetes history (n=30,528), breast cancer occurred in 1.62% (247/15,264) of GLP-1 users over the study period of 3.5 years, compared with 2.31% (353/15,264) of matched non-users. This corresponded to an OR of 0.695 (95% CI, 0.590 to 0.819; P<;0.0001), with an absolute risk reduction of 6.9 per 1000 (95% CI, 3.8 to 10.1%).
4Among women without diabetes, the OR was 0.653 (95% CI, 0.502–0.849; P=0.0014). Among women with diabetes, the OR was 0.723 (95% CI, 0.586–0.893; P=0.0026). Among Black women, the OR was 0.767 (P=0.0384), and among White women, the OR was 0.674 (P=0.0007).