GLP-1 drugs produce meaningful weight loss in breast cancer patients regardless of treatment type | Research

The takeaway

In 75 breast cancer patients, GLP-1 receptor agonists produced mean weight loss of 2.9 kg at 6 months and 4.2 kg (5%) at 12 months, with no patient characteristics predicting differential response.

-5% body weight at 12 months
GLP-1 drugs produced consistent weight loss in breast cancer patients regardless of tumor characteristics or concurrent cancer therapy

What the researchers found

Mean weight loss: -2.9 kg (95% CI -4.1 to -1.7) at 6 months, -4.2 kg (95% CI -5.5 to -2.9) at 12 months, -5% body weight at 12 months. No significant predictors of ≥5% weight loss in uni/multivariable analyses.

Why it matters

Obesity worsens breast cancer outcomes, and many cancer treatments cause weight gain. Finding that GLP-1 drugs produce meaningful weight loss during breast cancer treatment, without interference from cancer characteristics, supports their integration into oncology care.

How the study worked

Retrospective cohort of 75 breast cancer patients with GLP-1 RA prescriptions and follow-up weight data. Linear mixed effects model with random intercept for baseline weight.

What this study cannot tell us

Retrospective, no control group. Small sample (n=75). Most patients had diabetes (GLP-1 prescribed for metabolic indications). Weight loss modest compared to non-cancer populations. Potential survivor bias.

How to read the evidence

Retrospective cohort without controls. Provides hypothesis-generating data supporting clinical trials but insufficient for treatment recommendations.

When this study was published

Published in 2025.

The bigger picture

As GLP-1 drugs show potential cancer risk reduction (including prostate cancer) and produce weight loss during cancer treatment, they may become standard supportive care in oncology for obese patients.

Questions still open

Would GLP-1 drugs improve breast cancer outcomes through weight loss?
Are higher GLP-1 doses safe and effective in cancer patients?
Does GLP-1-mediated weight loss reduce breast cancer recurrence risk?

Common questions

Can you take GLP-1 drugs during breast cancer treatment?

This study found that 75 breast cancer patients who took GLP-1 drugs lost weight successfully despite concurrent cancer treatments. Weight loss was consistent regardless of cancer stage, type, or treatment. However, this was an observational study—discuss with your oncology team before starting any new medication.

Why is weight loss important for breast cancer patients?

Obesity is linked to worse breast cancer outcomes, higher recurrence risk, and more treatment side effects. Many cancer treatments also cause weight gain. Managing weight during and after treatment may improve outcomes, and GLP-1 drugs appear to be effective for this even in the cancer setting.

Read the original research

GLP-1 Receptor Agonist Use and Weight Change in Patients With Breast Cancer.

Oncology (Williston Park, N.Y.), null(7), 294-296

View on PubMed ↗Publisher’s paper ↗

Citation

Shen, Sherry; Bethina Liu Md; Chad Fanti Md; Maria Bromberg Mph; Yuan Chen PhD; Cassandra Chang; Neil M Iyengar Md. (2025). GLP-1 Receptor Agonist Use and Weight Change in Patients With Breast Cancer.. Oncology (Williston Park, N.Y.), null(7), 294-296. https://doi.org/10.46883/2025.25921046