Weight-Loss Drugs May Hold Clues for Cancer Outcomes, Researchers Investigate

Popular weight-loss drugs, such as semaglutides (Ozempic, Wegovy) and tirzepatides (Mounjaro, Zepbound), are increasingly being examined for their potential role in cancer outcomes, alongside their established use for obesity and diabetes. The American Association for Cancer Research's (AACR) 2026 Cancer Progress Report highlights that obesity is a significant risk factor for numerous cancers, making the metabolic and weight-loss effects of GLP-1 medications a subject of considerable interest for cancer researchers.

Investigating the Link

While some studies cited in the AACR report suggest that GLP-1 medications might reduce the risk of certain cancers, the report also notes that the overall evidence is mixed and more comprehensive research is required. Randomized clinical trials specifically designed to assess cancer outcomes associated with GLP-1 receptor agonist use have not yet been conducted, which remains the gold standard for scientific evidence.

Dr. Sai Yendamuri, a thoracic surgeon at Roswell Park Comprehensive Cancer Center, noted that obesity is the second leading cause of cancer, following smoking. He explained that other risk factors like alcohol consumption and poor nutrition are often intertwined with obesity. "So if obesity is related to cancer – both in terms of causing it and increasing its progression – the logical question is, would a drug that decreases obesity have an impact?"

Evidence from patients who have undergone metabolic surgery to reduce obesity suggests a correlation, with decreased cancer incidence observed in those individuals. Researchers have also begun studying patients taking GLP-1 receptor agonists, comparing their cancer incidence and survival rates to those not taking the medications. Many of these retrospective studies have indicated lower cancer risk and higher survival rates in patients using GLP-1s.

Mixed Findings and Potential Mechanisms

Despite the promising trends in some studies, not all research has found a definitive relationship, and a few studies have even suggested an increased risk for specific cancers, such as thyroid cancer. Yendamuri attributed these discrepancies to the nature of retrospective studies, which analyze existing data and can be influenced by numerous confounding variables.

His own team's research on obesity and lung cancer has consistently found that obesity increases the risk of lung cancer. Yendamuri also pointed out that the definition and measurement of obesity are evolving, with many researchers moving beyond Body Mass Index (BMI) to more precise assessments of body fat composition.

Two key findings from Yendamuri's research involve patients undergoing lung cancer surgery: those taking GLP-1 receptor agonists appeared to have a lower recurrence rate. Furthermore, patients with advanced-stage cancers receiving immunotherapy and also taking GLP-1s showed reduced recurrence rates. These findings suggest a potential role for GLP-1 medications in modulating the body's immune response to cancer cells, thereby enhancing its ability to fight the disease. The impact may vary depending on the cancer type, as the immune response plays a more critical role in some cancers than others, such as melanoma.

Future Directions and Prevention

While acknowledging that some of the observed benefits likely stem from weight loss, Yendamuri noted that not all patients experience substantial weight loss on GLP-1s. Future trials will aim to determine if the cancer benefits are dependent on weight loss. The hope is that, pending further research, GLP-1 drugs could eventually be considered a preventive measure against cancer. "More and more, we are realizing that apart from the treatment that you get for cancer, lifestyle modifications – exercise, decreasing weight, and now GLP-1 receptor agonists – will all have a role in both enhancing the treatment of cancer as well as preventing second cancers," Yendamuri stated.

He also emphasized the importance of continued funding for cancer research, including that supported by the National Cancer Institute, to drive new discoveries and advance the understanding of cancer prevention and treatment.