Medical

GLP-1 Weight-Loss Drugs Linked to Lower Cancer Risk and Mortality in New U.S. Study

A groundbreaking study has revealed that GLP-1 receptor agonists, a class of medications widely used for weight loss and diabetes management, may reduce the risk of obesity-related cancers by approximately 7% and lower overall mortality by 8% in people with obesity and diabetes. Conducted in the United States, this research highlights the potential of drugs like Ozempic, Wegovy, and Zepbound to offer health benefits beyond their well-known effects on blood sugar control and weight reduction. As obesity continues to be a major public health concern, these findings could reshape how we approach chronic disease prevention.

Understanding GLP-1 Drugs and Their Growing Popularity

GLP-1 receptor agonists, originally developed to treat type 2 diabetes, have gained widespread attention for their effectiveness in promoting weight loss. Medications such as semaglutide (sold as Ozempic and Wegovy) and tirzepatide (Zepbound) work by mimicking hormones in the gut and brain that regulate appetite and feelings of fullness. By slowing stomach emptying and signaling satiety, these drugs help users reduce food intake, leading to significant weight loss. In the U.S., an estimated 12% of adults have used GLP-1 drugs for diabetes or weight management, reflecting their growing role in addressing obesity, a condition affecting over 40% of Americans, according to the Centers for Disease Control and Prevention (CDC).

The rise of GLP-1 drugs has been fueled by their proven benefits in clinical settings. Beyond weight loss, studies have shown these medications can lower the risk of heart disease, stroke, and kidney issues. However, the latest research, presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, adds a new dimension to their potential: reducing obesity-related cancers and overall mortality.

The Study: Key Findings on Cancer and Mortality

The study, led by Lucas Mavromatis, a medical student at NYU Grossman School of Medicine, analyzed data from 43 U.S. health systems, tracking over 170,000 adults with obesity (body mass index of 30 or higher) and diabetes. Participants were divided into two groups: those taking GLP-1 drugs and those using DPP-4 inhibitors, another class of diabetes medications that do not promote weight loss. The groups were matched for characteristics like age and health status to ensure a fair comparison. Over an average follow-up period of 3.9 years, researchers observed significant differences in health outcomes.

The results were striking. Individuals taking GLP-1 drugs had a 7% lower risk of developing one of 14 obesity-related cancers, including colon, rectal, and pancreatic cancers, compared to those on DPP-4 inhibitors. Specifically, the GLP-1 group recorded 2,501 new cancer cases, while the DPP-4 group had 2,671. Notably, women on GLP-1 drugs experienced an 8% lower cancer risk, while the benefit was not statistically significant in men. The study also found an 8% reduction in all-cause mortality among the GLP-1 group, with 2,783 deaths compared to 2,961 in the DPP-4 group [U.S. News].

These findings suggest that GLP-1 drugs may offer a protective effect against cancers linked to obesity, a major risk factor for diseases like colorectal and breast cancer. Obesity is the second leading cause of cancer in the U.S., contributing to more than one in 20 cancer cases, according to the National Cancer Institute. The study’s lead author, Lucas Mavromatis, emphasized that while no medications have been proven to directly lower obesity-related cancer risk, these results are a promising step toward identifying preventive treatments.

Why GLP-1 Drugs Might Reduce Cancer Risk

The exact mechanisms behind the reduced cancer risk are not fully understood, but researchers have proposed several theories. Obesity is known to drive chronic inflammation, which can promote cancer development. GLP-1 drugs may reduce inflammation, potentially lowering the risk of tumor formation. Additionally, these medications improve insulin sensitivity and lower insulin levels, which may reduce signals that drive cancer cell growth, as noted by Lindsey Wang, a medical student and research scholar [New York Post].

Another study, published in The Lancet’s eClinicalMedicine journal, found that GLP-1 drugs reduced obesity-related cancer risk by 41% compared to bariatric surgery, despite the surgery leading to greater weight loss. This suggests that the benefits of GLP-1 drugs extend beyond weight reduction, possibly due to their anti-inflammatory effects or other biological mechanisms [The Lancet]. Lead researcher Dror Dicker from Tel Aviv School of Medicine speculated that these drugs might alter cellular processes like apoptosis (programmed cell death), which could inhibit cancer development.

However, the ASCO study noted that the benefits were more pronounced in women, with an 8% lower cancer risk and a 20% lower risk of death from any cause. The reasons for this gender disparity are unclear but may involve differences in drug metabolism, hormone levels, or weight loss patterns. Further research is needed to explore these factors and confirm the findings in broader populations, including those without diabetes.

Broader Implications for Public Health

The study’s findings have significant implications for public health, particularly in the U.S., where obesity-related diseases place a heavy burden on healthcare systems. Obesity is linked to 13% of premature deaths and contributes to conditions like heart disease, diabetes, and cancer, costing billions annually in medical expenses. If GLP-1 drugs can reduce cancer risk and mortality, they could become a key tool in preventive medicine, potentially saving lives and reducing healthcare costs.

ASCO President Robin Zon, who was not involved in the study, highlighted its importance: “Given the clear link between obesity and cancer, defining the clinical role of GLP-1 medications in cancer prevention is critical.” She cautioned that the study is observational and does not prove causation, but it provides a strong foundation for future research [ASCO]. Long-term studies are needed to confirm the durability of these effects and ensure that GLP-1 drugs do not increase risks for other types of cancer, such as medullary thyroid cancer, which has been flagged in warning labels for some GLP-1 medications.

Challenges and Considerations

While the findings are promising, GLP-1 drugs are not without challenges. Common side effects include nausea, vomiting, and diarrhea, though these are often temporary and manageable, according to Chika Anekwe, Obesity Medicine Clinical Director at Massachusetts General Hospital [Harvard Health]. More serious risks, such as gastrointestinal issues or rare cases of stomach paralysis, have also been reported. Additionally, the high cost of these medications—often thousands of dollars per month—limits access for many patients, particularly those without insurance coverage. The recent FDA crackdown on cheaper, compounded versions of GLP-1 drugs has further raised concerns about affordability and access [The New York Times].

Another issue is discontinuation. Many patients stop taking GLP-1 drugs due to cost or side effects, which can lead to rapid weight regain, potentially negating health benefits. Obesity is a chronic condition, and long-term use may be necessary to sustain outcomes. Researchers are also exploring newer GLP-1 formulations, such as oral versions of semaglutide (e.g., Novo Nordisk’s Rybelsus), which could improve accessibility if approved for obesity treatment [Fierce Pharma].

What’s Next for GLP-1 Research?

The ASCO study is a significant step, but it raises as many questions as it answers. Researchers are calling for randomized controlled trials to validate these findings and explore the drugs’ effects in people without diabetes. Studies are also needed to assess long-term safety and the potential for GLP-1 drugs to prevent non-obesity-related cancers. Additionally, the development of oral GLP-1 drugs and dual-action medications like CagriSema, which could achieve up to 25% weight loss, may further enhance their impact.

As the science evolves, healthcare providers and policymakers will need to balance the benefits of GLP-1 drugs with their costs and risks. For now, these medications offer hope for millions of Americans battling obesity and its associated health challenges, potentially transforming the landscape of preventive care.