GLP-1 Drugs Show No Increased Cancer Risk in Large Meta-Analysis of 94,000 Patients
Key Insights
A comprehensive meta-analysis of 48 randomized controlled trials involving 94,245 adults found that GLP-1 (search) drugs like Ozempic and Zepbound do not increase the risk of obesity (search)-related cancers.
The study examined 13 different cancer types including breast, thyroid, pancreatic, and kidney cancers, finding no significant difference in cancer risk between GLP-1 (search) users and placebo recipients.
Researchers emphasize that longer-term studies with at least 5 years of follow-up are needed to fully assess cancer outcomes, as the median follow-up in current trials was only 70 weeks.
A large-scale meta-analysis published in Annals of Internal Medicine has found that GLP-1 (search) receptor agonists do not increase the risk of obesity (search)-related cancers, providing important safety data for these increasingly popular medications. The comprehensive review analyzed 48 randomized controlled trials involving 94,245 adults with type 2 diabetes (search), overweight, or obesity.
Study Design and Scope
Researchers led by Dr. Cho-Han Chiang, a hematology/oncology fellow at Northwell Health Cancer Institute (search), examined trials that assessed FDA-approved GLP-1 (search) drugs and dual agonists. The analysis included more than 51,000 people who took GLP-1 medications and nearly 43,000 who received placebo, with a median follow-up period of 70 weeks.
The study population was diverse, with 26 trials enrolling patients with type 2 diabetes (search), 18 including patients with overweight or obesity (search), and four enrolling people with both conditions. Semaglutide (Ozempic/Wegovy) was the most commonly studied drug, appearing in 42% of trials, followed by liraglutide (Saxenda/Victoza) in 21% of studies.
Cancer Risk Assessment
The meta-analysis examined 13 different obesity (search)-related cancers, including breast, thyroid, pancreatic, kidney, colorectal, esophageal, liver, gallbladder, ovarian, endometrial cancers, as well as multiple myeloma (search) and meningioma. Results showed no significant difference in cancer odds between GLP-1 (search) users and placebo recipients across all cancer types examined.
"GLP-1 (search) [drugs] probably do not increase the risk of cancer," Chiang explained, noting that the findings address previous concerns about thyroid and pancreatic cancer (search) risks associated with these medications.
The certainty of evidence was rated as moderate for thyroid cancer (search), pancreatic cancer (search), breast cancer (search), and kidney cancer (search), while it was low for other cancer types due to imprecision in the data.
Clinical Implications
The findings remained consistent across multiple subgroup analyses, including stratification by trial duration, patient population (diabetes vs. obesity (search)), and drug type (GLP-1s vs. dual agonists). Sensitivity analyses excluding studies with moderate or high risk of bias, and those focusing only on semaglutide or tirzepatide (Mounjaro/Zepbound), also showed similar results.
"Clinically, these findings support the overall safety of GLP-1s with regard to cancer, which is important given the rapid growth in these drugs use for diabetes, obesity (search) and cardiometabolic disease," Chiang told Healio.
Dr. Bassel El-Rayes, deputy director of the O'Neal Comprehensive Cancer Center at the University of Alabama at Birmingham, found the results reassuring. "This study gives us more reassurance about using these drugs in the treatment of things like obesity (search) and type 2 diabetes (search)," he explained.
Study Limitations and Future Research
The research team acknowledged important limitations, particularly the relatively short follow-up period. Since many cancers develop slowly over years, the median 70-week observation period may not capture long-term cancer risks or benefits.
"Long-term randomized or observational studies with at least 5 years of follow-up and prespecified, standardized cancer endpoints are needed to clarify potential risks or benefits with GLP-1s," Chiang emphasized.
Dr. Kandace McGuire, a breast surgeon at Virginia Commonwealth University who was not involved in the study, noted that patients prescribed GLP-1s should be monitored for far longer, particularly for slow-growing diseases like breast and thyroid cancers.
Contrast with Previous Studies
The meta-analysis findings differed from earlier observational studies that suggested GLP-1 (search) drugs might help prevent cancer. Chiang attributed this discrepancy to differences in study design and follow-up duration between randomized controlled trials and observational studies.
"The discrepancy likely stems from the fact that these are two different types of study design (randomized controlled trials vs. observational, nonrandomized data) and also differences in follow-up time," he explained.
Regulatory Context
The FDA currently warns that individuals with a personal or family history of a rare thyroid cancer (search) should avoid certain GLP-1 (search) drugs. However, Chiang noted that this warning is based on older studies conducted in rodents, and results from animal studies often differ when translated to humans.
Dr. Susan Wolver, director of the Medical Weight Loss Program at VCU Health, emphasized that cancer prevention is not typically the primary indication for GLP-1 (search) prescriptions. "Nobody comes to me and says, 'I'd like to go on some medication to reduce my cancer risk,'" she noted, highlighting that these medications are primarily prescribed for weight management, heart failure, or sleep apnea.
The research provides important safety data as GLP-1 (search) drugs continue to gain widespread use for multiple therapeutic indications, though longer-term studies will be essential for definitive conclusions about cancer risk.