Weight Loss Drugs May Reduce the Risk of Some Cancers

Researchers looked at the rates of lung cancer plus more than a dozen obesity-related cancers and found that people taking GLP-1s had a reduced overall risk of cancer compared with those not taking the drugs — particularly for ovarian and endometrial cancers and some brain tumors.

“Obesity is one of the strongest risk factors for cancer, yet we’ve had very little data on whether new obesity drugs affect cancer risk,” says the senior study author, Serena Jingchuan Guo, MD, PhD, an associate professor and the AI director at the Purdue University College of Pharmacy in Indiana.

“With GLP-1 medicines being used by millions of people today, it was the right time to ask this question. Our findings suggest that their impact may extend beyond weight loss and diabetes into certain cancer prevention,” says the joint senior study author Jiang Bian, PhD, an associate dean of data science at the Indiana University School of Medicine in Indianapolis and the chief data scientist at Regenstrief Institute and IU Health.

Study Looked at Lung Cancer and 13 Obesity-Related Cancers

Using electronic health records from a database of more than 20 million people in Florida, Georgia, and Alabama, the research team identified individuals who were eligible for obesity medications and who did not have a medical history of cancer.

More than 43,000 adults who had been prescribed a GLP-1 medication — tirzepatide (Mounjaro, Zepbound), semaglutide (Ozempic, Wegovy), or liraglutide (Saxenda) — were matched with a similar-size group of people who were not taking a GLP-1. Participants were 52 years old on average, 68 percent were female, and 44 percent identified as non-Hispanic white. Half the participants had type 2 diabetes, and almost half had obesity.

The researchers were looking at rates of lung cancer and 13 obesity-related cancers: liver, thyroid, pancreatic, bladder, colorectal, kidney, breast, endometrial, meningioma (a type of brain tumor), upper gastrointestinal, ovarian, prostate, and multiple myeloma). Taking a GLP-1 was linked to the biggest risk reductions in:

• Ovarian cancer, with a 47 percent risk reduction
• Meningioma, with a 31 percent risk reduction
• Endometrial cancer, with a 25 percent risk reduction

The results also showed a small increase in kidney cancer among people taking GLP-1s — particularly those under age 65 and overweight — which the researchers describe as not statistically significant, but worth monitoring in future research.

Why Is Obesity a Risk Factor for Cancer, and How Might GLP-1s Protect Against It?

“GLP-1s likely reduce cancer risk mostly by helping people lose weight, lowering their blood sugar, and decreasing inflammation — factors we know drive obesity-related cancers. There’s also some early evidence that the drugs may directly influence cancer biology, though that remains under study,” says Dr. Guo.

“We know that weight reduction is an important cancer risk reduction intervention and we're learning how different weight loss interventions can contribute to that,” says Arif Kamal, MD, the chief patient officer at the American Cancer Society, who was not part of the new research.

“It’s encouraging to see that GLP-1s may be one way to get there, but we need to learn more over time about whether how you get to that weight loss is important — and whether there are other biological effects in addition to weight loss that are associated with GLP-1s that also speak to lower cancer risk,” Dr. Kamal says.

New Pathways for Future Research on Obesity, GLP-1s, and Cancer Risk

The new study strengthens the growing evidence that GLP-1s may have cancer-preventive effects in a broader population, says Nupur Kikani, MD, an assistant professor in the department of endocrine neoplasia and hormonal disorders at the University of Texas MD Anderson Cancer Center in Houston.

Among the most notable findings for her were the types of cancer risk most affected by GLP-1 use. “Endometrial and ovarian cancers are common and highly linked to obesity and hormonal factors. Reducing their risk has meaningful implications for health and oncology,” says Dr. Kikani, who was not involved in the new research.

Kamal agrees that the findings on estrogen-related cancers may be most impactful. “These are cancers that don't have screening tests associated with them,” he says. “Endometrial cancer, for example, is growing in the U.S. — particularly among Black populations — and oftentimes has high mortality, so it's a scary cancer that's helpful to imagine we could prevent.”

Because the findings highlight early evidence from a real-world population snapshot, the study authors say that longer-term data collected from a larger sample size would be beneficial for future studies.

Kikani adds that the study’s short-term follow-up time may not fully capture the long-term effects of cancer development and that the observational study design can only point toward association rather than causation.

“The benefits are promising but not definitive. They should be weighed against other health side effects and drug costs,” says Kikani, underscoring that patients should discuss individualized options with their doctors. “GLP-1s remain primarily indicated for diabetes and weight management, with cancer risk reduction as a potential added benefit.”