GLP-1 drugs linked to improved breast cancer survival in large cohort study

A study has found that glucagon-like peptide-1 receptor agonist use was associated with lower all-cause mortality and reduced recurrence risk among breast cancer patients with obesity or type 2 diabetes

A large observational study by researchers at Virginia Commonwealth University, Richmond, Virginia, USA has linked glucagon-like peptide-1 (GLP-1) receptor agonists to improved survival and a lower risk of recurrence among some patients with breast cancer, although researchers said randomised clinical trials would be needed before the drugs could inform cancer treatment decisions.

The research examined electronic health records from more than 840,000 patients diagnosed with breast cancer between 2006 and 2023. The study assessed whether GLP-1 receptor agonists, a class of medicines widely used to treat type 2 diabetes (T2DM) and obesity, were associated with long-term breast cancer outcomes.

The findings suggested that GLP-1 receptor agonists use was associated with a lower risk of death from any cause during 10 years of follow-up. Among breast cancer survivors who had used the medicines for diabetes or obesity, the study also found a significantly lower risk of cancer recurrence during the decade after initial treatment.

“GLP-1 drugs may offer protective benefits potentially improving survival and recurrence risk in some female patients with breast cancer – whether this is related to weight control, improve cardiovascular health or other mechanisms remains to be studied,” said Dr. Bernard F. Fuemmeler, senior author of the study, associate director for population sciences and the ‘Gordon D. Ginder, MD, Chair in Cancer Research’ at Virginia Commonwealth University Massey Comprehensive Cancer Center.

Breast cancer remains the most common cancer among women in the USA, apart from skin cancer, and accounts for nearly one third of all female cancer cases. The average lifetime risk that a woman in the USA will develop breast cancer is about 13 per cent. Obesity and T2DM have both been associated with more aggressive breast cancer and poorer outcomes which has placed metabolic health under closer scrutiny in oncology research.

GLP-1 receptor agonists mimic the activity of the GLP-1 hormone, which helps to regulate blood glucose, appetite and body weight. The drug class was first approved to treat T2DM in 2005 and later gained approval for weight management in 2021. Since 2020, use of these medicines has risen sharply around the world.

“Our findings align with emerging preclinical research and contribute to a growing body of literature related to GLP-1 receptor agonists use in oncology settings,” said Dr. Kristina L. Tatum, lead author of the study and a researcher at the Virginia Commonwealth University, School of Public Health.

The authors cautioned that the study identified associations rather than proof of causation. Because the analysis was retrospective, it could not establish whether the use of GLP-1 receptor agonists had directly improved survival or reduced recurrence, nor could it determine whether any apparent benefit resulted from weight loss, improved cardiovascular health, better glucose control, anti-inflammatory effects or other biological mechanisms.

Further investigation will also be needed to assess whether outcomes vary by breast cancer subtype, tumour biology, treatment history, drug type, dose, duration of use or degree of weight change. These questions are clinically important because breast cancer is not a single disease and because rapid weight loss in cancer survivors may carry risks – including loss of lean body mass – if not carefully managed.

“Our study underscores the potential of GLP-1 receptor agonists as an adjunct strategy for improving cancer-related outcomes among patients with breast cancer, although clinical trials are needed to inform effective therapeutic approaches and clinical decision making,” Fuemmeler said.

The researchers said future randomised clinical trials would be needed to test whether GLP-1 receptor agonists could safely and effectively support breast cancer care in defined patient groups. Until then, the findings should be viewed as a signal that metabolic treatment may have relevance beyond diabetes and obesity, rather than as evidence to prescribe GLP-1 receptor agonists specifically to improve cancer outcomes.

For further reading please visit: 10.1001/jamanetworkopen.2026.12133