GLP-1 receptor agonists tied to 7% lower obesity-related cancer risk in diabetes study

A large observational analysis of 170,030 US adults who have both type 2 diabetes and obesity found that those who started a GLP-1 receptor agonist had a 7% lower risk of being diagnosed with one of 14 obesity-related cancers than those who started a DPP-4 inhibitor, a different class of diabetes drug that does not cause weight loss or weight gain ^[1]. The results were released ahead of the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, held May 31 to June 3, 2025, in Chicago ^[1].

The study, led by Lucas A. Mavromatis, a medical student at NYU Grossman School of Medicine, drew on records from 43 US health systems covering 2013 to 2023 ^[1]. The researchers used propensity score matching to build comparable groups without randomizing patients. After matching, each group had 85,015 patients. Their average age was 56.8 years, about half were women, and the average BMI was 38.5, above the cutoff of 30 that defines obesity ^[1].

Over a mean follow-up of 3.9 years, there were 2,501 new diagnoses of obesity-related cancer in the GLP-1 group and 2,671 in the DPP-4 group ^[1]. The 7% lower risk was reported as a hazard ratio of 0.93 (95% CI, 0.88-0.98; P = .005). All-cause mortality was 8% lower in the GLP-1 group (HR, 0.92; P = .001) ^[1]. Results varied by cancer type, with the protective association driven by colon and rectal cancers ^[1].

The 14 cancers linked to obesity include those of the esophagus, colon, rectum, stomach, liver, gallbladder, pancreas, kidney, postmenopausal breast, ovary, endometrium and thyroid, plus multiple myeloma and meningioma ^[1]. Most patients in the study took liraglutide (Victoza), which was approved in 2010, though some took the more potent semaglutide, sold as Ozempic for type 2 diabetes and Wegovy for weight loss ^[1]. GLP-1 sales topped $40 billion in 2024, and semaglutide has been shown to help patients lose an average of 10% to 15% of their weight ^[1].

Mavromatis was direct about the limits of the finding. "While there's biologically plausible links between GLP-1 use and reduced obesity related cancer incidents, it has yet to be shown in any human studies," he said, adding that the long-term effect of these weight-management therapies on obesity-related cancer incidence is unknown ^[1].

ASCO president Robin Zon, MD, called the result an "intriguing hypothesis" and said it would also be worth studying patients who do not have diabetes ^[1]. ASCO Chief Medical Officer Julie R. Gralow, MD, said that if 12% of the population uses these drugs, "it's certainly worth studying in a way that we can get solid evidence to support whether or not there is a role to be using these drugs" ^[1]. A KFF survey cited in the report found about 1 in 8 US adults, or 12%, have taken a GLP-1 ^[1].

Mavromatis said a randomized trial testing whether the drugs prevent cancer would be "ideal," but that the size and duration needed to produce meaningful evidence would be challenging ^[1]. Funding for the study came from the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health ^[1].

Why it matters for patients

The study adds a favorable signal about long-term health for people already taking or considering a GLP-1, but it does not prove that these drugs prevent cancer. It compared patients who were matched rather than randomly assigned, so it can show an association but not cause and effect ^[1].

The findings come from people who had both type 2 diabetes and a BMI of at least 30, so they do not directly describe people who use these drugs only for weight loss without diabetes ^[1]. The follow-up averaged 3.9 years, and longer-term effects have not been reported ^[1]. No cancer-prevention use appears among the approved indications described in the report ^[1].

Coverage is another practical factor. Cost concerns have led many employers to limit insurance coverage to patients taking the drugs for diabetes or cardiovascular reasons and to stop paying when the drugs are used solely for weight loss ^[1]. The report does not say whether a cancer-related finding would change any coverage rules.

What happens next

The work was presented as Abstract 10507 at the ASCO annual meeting ^[1]. No randomized trial designed to test whether GLP-1s prevent cancer has been reported, and the experts quoted did not describe one as under way ^[1]. Open questions include whether the same pattern would appear in people without diabetes and how semaglutide and other GLP-1s compare with the liraglutide that most patients in this study received ^[1].