McDonald · JCO oncology practice 2026 · retrospective propensity-matched cohort study · n=111646

GLP-1 Agonists Are Associated With a Significant Reduction in Breast Cancer Incidence in Women.

Cited 4 times in the scientific literature.

Level 3 - non-randomized controlled study

Retrospective propensity score-matched cohort study

PubMed 42227662 · doi:10.1200/OP-26-00485 · record verified 2026-08-26

What was done

This retrospective cohort study used electronic health records (January 2022 to June 2025) of 111,646 women aged 45–80 years with BMI ≥25 who underwent breast imaging with documented outcomes (median age 61 years). GLP-1 exposure was defined as a first prescription prior to the imaging examination. Researchers performed 1:1 nearest-neighbor propensity score matching on age, race, ethnicity, highest BMI, breast density, and type 2 diabetes history, analyzing breast cancer detection with matched logistic regression.

What was found

GLP-1 exposure was associated with lower breast cancer incidence in the overall cohort (OR, 0.649 [95% CI, 0.569 to 0.741]; P < .0001). In the propensity-matched sample (30,528 observations; 600 cancer cases), GLP-1 exposure remained significantly associated with reduced breast cancer detection (OR, 0.695 [95% CI, 0.590 to 0.819]; P < .0001).

Why it matters

The findings suggest GLP-1 receptor agonists are associated with reduced breast cancer risk in overweight and obese women independent of baseline BMI, breast density, and diabetes. This highlights the need to prospectively investigate GLP-1 agonists for breast cancer prevention.

Limits

As an observational retrospective study from a single academic health network, selection bias and unmeasured confounding (such as family history, parity, and lifestyle factors) cannot be excluded. Exposure was based on prescription orders rather than confirmed adherence, dose, or duration of therapy, and the specific degree of on-treatment weight loss was not evaluated.

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