Weight-loss drugs may lower cancer risk in people with diabetes, a study suggests

Key Points

• The study of 170,000 U.S. adults with diabetes suggests that those on GLP-1 receptor agonists had a 7% lower risk of obesity-related cancers and an 8% lower all-cause mortality over a four-year period compared to users of other diabetes drugs.
• Researchers analyzed data from 43 health systems, matching patients with obesity and diabetes on GLP-1 drugs against those taking medications like sitagliptin.
• As an observational study, the findings cannot establish causation, prompting calls for randomized trials to confirm whether these drugs directly reduce cancer risk.
• The reduction in cancer risk was statistically significant among women but not in men, possibly due to differences in drug concentration, weight loss, metabolism or hormonal factors.

Excess body weight can raise the risk of certain cancers, leading researchers to wonder whether blockbuster drugs like Wegovy, Ozempic and Zepbound could play a role in cancer prevention.

Now, a study of 170,000 patient records suggests there's a slightly lower risk of obesity-related cancers in U.S. adults with diabetes who took these popular medications compared to those who took another class of diabetes drug not associated with weight loss.

This type of study can't prove cause and effect, but the findings hint at a connection worth exploring. More than a dozen cancers are associated with obesity.

“This is a call to scientists and clinical investigators to do more work in this area to really prove or disprove this,” said Dr. Ernest Hawk of MD Anderson Cancer Center in Houston, who was not involved in the study.

The findings were released Thursday by the American Society of Clinical Oncology and will be discussed at its annual meeting in Chicago. The study, funded by the National Institutes of Health, was led by Lucas Mavromatis, a medical student at New York University’s Grossman School of Medicine.

“Chronic disease and chronic disease prevention are some of my passions,” said Mavromatis, a former research fellow with an NIH training program.

GLP-1 receptor agonists are injections used to treat diabetes, and some are also approved to treat obesity. They work by mimicking hormones in the gut and the brain to regulate appetite and feelings of fullness. They don't work for everyone and can produce side effects that include nausea and stomach pain.

In the study, researchers analyzed data from 43 U.S. health systems to compare two groups: people with obesity and diabetes who took GLP-1 drugs and other people with the same conditions who took diabetes drugs like sitagliptin. The two groups were equal in size and matched for other characteristics.

After four years, those who took GLP-1 drugs had a 7% lower risk of developing an obesity-related cancer and an 8% lower risk of death from any cause compared to those who took the other type of diabetes drug. There were 2,501 new cases of obesity-related cancer in the GLP-1 group compared to 2,671 cases in the other group.

The effect was evident in women, but not statistically significant in men. The study couldn't explain that difference, but Mavromatis noted that differences in blood drug concentration, weight loss, metabolism or hormones could be at play.

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