A large, retrospective study conducted by scientists at the University of Texas at San Antonio (UT San Antonio) suggests that people taking glucagon-like peptide-1 (GLP-1) receptor agonists — medications that are widely prescribed for metabolic disease — have a significantly lower risk of developing colorectal cancer compared with those taking aspirin.
“This is astounding to know that a drug for diabetes and obesity could have a significant anticancer effect, and I believe this could have a huge impact on public health going forward,” said Colton Jones, MD, a first-year fellow in the Division of Hematology and Medical Oncology at the Joe R. and Teresa Lozano Long School of Medicine at UT San Antonio.
The findings were presented in January at the 2026 American Society of Clinical Oncology Gastrointestinal Cancers Symposium.
The study was led by Jones under the mentorship of Sukeshi Patel Arora, MD, a professor in the Division of Hematology and Medical Oncology at the Long School of Medicine and a gastrointestinal oncologist at Mays Cancer Center.
“This study highlights how medications developed for metabolic disease may have far broader implications for oncology. Dr. Jones approached this question thoughtfully, and the findings open the door for future research that could reshape prevention and treatment strategies,” said Arora.
Head-to-head comparison with aspirin
While aspirin has been investigated for decades as a preventive therapy for colorectal cancer, its use has been limited due to adverse side effects such as an increased risk of bleeding. In recent years, the U.S. Preventive Services Task Force downgraded its recommendation for aspirin use in primary colorectal cancer prevention.
More than 20 million Americans currently take GLP-1 receptor agonists. This prompted the research team to explore whether these widely used drugs might also offer protection against cancer.
To examine this question, the team analyzed de-identified health records from a large commercial database. The study included 281,656 participants, divided between people who had been prescribed a GLP-1 receptor agonist and those taking aspirin.
Patients were matched to account for demographics, comorbidities and cancer risk factors.
Lower colorectal cancer incidence with GLP-1s
Across the study population, there was a 36% reduction in colorectal cancer risk in the GLP-1 group compared with aspirin users. The findings remained consistent at 12 months and 36 months, and the benefit was observed regardless of body mass index, weight loss or diabetes status.
In the study, the greatest reduction in colorectal cancer risk was seen in younger adults. Participants who began taking GLP-1 medication between ages 18 and 44 experienced the strongest protective association. This is especially important considering a recent finding that colorectal cancer has now taken the lead as the top cause of cancer-related death among people under the age of 50 in the United States.
Differences among GLP-1 medications
Various GLP-1 medications, including semaglutide, liraglutide and dulaglutide, were each associated with a significant reduction in colorectal cancer risk. Liraglutide demonstrated the largest effect, followed by dulaglutide and semaglutide.
Tirzepatide, a newer dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) agonist, did not show a benefit in this analysis, which Jones said may be due to its more recent approval and smaller sample size.
The protective association was also not observed in participants who used tobacco or those with atherosclerotic disease.
Mechanistic rationale and next steps
Jones said the observed benefit is likely multifactorial. GLP-1 receptor agonists improve insulin sensitivity and reduce chronic inflammation, both of which are known drivers of cancer development. GLP-1 receptors are also expressed in the colon, where activation may improve the gut microbiome and reduce inflammation.
In addition, previous studies suggest GLP-1 drugs may directly inhibit a key mechanistic target of rapamycin (mTOR)-signaling pathway involved in tumor growth and proliferation.
Since this study was retrospective, it demonstrates association but not causation between GLP-1 medications and colorectal cancer risk. Longitudinal clinical trials are needed before GLP-1 receptor agonists could be recommended specifically for cancer prevention.
Jones said his future research will focus on evaluating GLP-1 therapies in other high-risk gastrointestinal cancers and on designing long-term prospective studies to determine whether these medications could one day play a role in primary cancer prevention.
“Especially in high-risk gastrointestinal cancers that have no primary prevention medication, early research shows amazing benefits that could potentially be a game changer in how we prevent cancer on a worldwide scale,” Jones said.
Colton Jones et al. GLP-1 receptor agonist vs aspirin for primary prevention of colorectal cancer: Evidence from a real-world head-to-head comparison. Journal of Clinical Oncology 44, 18-18(2026). DOI:10.1200/JCO.2026.44.2_suppl.18