Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are highly effective medications for treating type 2 diabetes and obesity. However, concerns about GLP-1 cancer risk prompted a new systematic review and meta-analysis of short-term randomized controlled trials (RCTs). The review examined data from 48 placebo-controlled trials, encompassing 94,245 participants. Therefore, it provides a crucial snapshot of the early safety profile for these increasingly popular drugs.
Key Findings: Neutral GLP-1 Cancer Risk in Short-Term RCTs
The systematic review indicates that GLP-1RAs probably have little or no effect on the risk for several major cancer types. Specifically, researchers found no significant increase in risk for thyroid cancer (OR, 1.37 [95% CI, 0.82 to 2.31]), pancreatic cancer (OR, 0.84 [CI, 0.53 to 1.35]), breast cancer (OR, 0.95 [CI, 0.60 to 1.49]), or kidney cancer (OR, 1.12 [CI, 0.78 to 1.60]). These findings were based on moderate-certainty evidence. Furthermore, the analysis determined that the agents may have little or no effect on the risk of colorectal, esophageal, liver, gallbladder, ovarian, or endometrial cancer, multiple myeloma, or meningioma. Nevertheless, the certainty of this evidence remains low for these specific outcomes. The effect on gastric cancer remains highly uncertain, as the data was inconclusive. The results consistently held across multiple sensitivity and subgroup analyses, including those specifically looking at semaglutide and tirzepatide.
Conflicting Real-World Data: Potential Protective Effects
While the meta-analysis of RCTs suggests a neutral effect on GLP-1 cancer risk, other large, real-world observational studies offer a contrasting perspective. Consequently, these data complicate the overall clinical picture. Compared to other diabetes medications, including insulin or metformin, GLP-1RA use is associated with a significantly lower risk of several gastrointestinal cancers, such as oesophageal, colorectal, and liver cancer. Moreover, retrospective cohort studies in adults with overweight or obesity show that GLP-1RA use correlates with a lower overall cancer risk, specifically for hormone-sensitive malignancies like endometrial and ovarian cancer, and meningioma. However, a single study did note a marginal trend toward increased kidney cancer risk, which warrants further investigation. Importantly, these retrospective studies suggest a dual benefit, confirming efficacy in blood sugar control and weight loss while potentially offering a protective effect against certain obesity-associated cancers. Physicians should carefully weigh this information against the conservative findings of short-duration RCTs.
The major limitation of the current systematic review lies in the short follow-up duration of the included trials. Therefore, a definitive conclusion on long-term cancer risk requires longer-term studies designed specifically for oncologic outcomes. This is particularly crucial as GLP-1RAs are often prescribed for chronic use.
Frequently Asked Questions
Q1: Do GLP-1 Receptor Agonists increase the risk for thyroid or pancreatic cancer?
Current systematic review and meta-analysis data from randomized controlled trials suggest GLP-1RAs probably have little or no effect on the risk for thyroid or pancreatic cancer over the short term (moderate certainty evidence).
Q2: What is the primary limitation of the current cancer risk data for GLP-1RAs?
The primary limitation is that the trials reviewed were not specifically designed to evaluate cancer outcomes and had a short follow-up duration. Longer-term studies are essential to fully clarify any potential long-term risks or benefits.
Q3: Does real-world evidence suggest a protective effect against any cancers?
Yes. Large observational studies suggest that GLP-1RA use may be associated with a reduced risk of several obesity-associated cancers, including colorectal, liver, endometrial, and ovarian cancers, when compared to other non-GLP-1RA diabetes therapies.
References
- Ko A et al. Risk for Cancer With Glucagon-Like Peptide-1 Receptor Agonists and Dual Agonists : A Systematic Review and Meta-analysis. Ann Intern Med. 2025 Dec 09. doi: 10.7326/ANNALS-25-02237. PMID: 41359966.
- Nagendra L et al. Semaglutide and cancer: A systematic review and meta-analysis. Diabetes Metab Syndr. 2023 Jul-Aug;17(7):102804.
- Wang L, Xu R, Kaelber DC, Berger NA. Glucagon-like peptide 1 receptor agonists and 13 obesity-associated cancers in patients with type 2 diabetes. JAMA Netw Open. 2024;7(7):e2421305.
- Faur AM et al. Assessment of thyroid carcinogenic risk and safety profile of GLP1-RA semaglutide (Ozempic) therapy for diabetes mellitus and obesity: a systematic literature review. Int J Mol Sci. 2024;25(8):4346.