Weight loss drugs slash risk of 4 types of cancer by 50% or more, study finds

For this study, researchers analyzed the health data from a national database of more than 229,000 obese, non-diabetic people.

“Most previous studies examining GLP-1 medications and cancer risk were conducted in patients with type 2 diabetes,” Kamat explained.

“However, the majority of individuals now receiving GLP-1 medications are using them for obesity management and do not have diabetes. This is the population that has been invisible in the literature, and it is now the largest group using these drugs. They are younger, they don’t have diabetes, and they are experiencing some of the sharpest increases in obesity-associated cancers we’ve seen in decades,” she said.

Researchers have linked 13 cancers to obesityincluding:

• Breast
• Colorectal
• Endometrial
• Esophageal
• Gallbladder
• Kidney
• liver
• Meningioma (a type of brain tumor)
• Multiple myeloma (a type of bone marrow cancer)
• Ovarian
• Pancreatic
• Stomach (gastric)
• Thyroid

Between December 2014 and June 2025, 38% of study participants received a GLP-1 prescription, and the remaining 62% received diet and exercise counseling.

At the study’s conclusion, researchers found that participants who took GLP-1 medications containing semaglutide or tirzepatide had a 41% decrease in their overall risk of developing an obesity-related cancer.

“A 41% reduction across more than 229,000 patients is not a small signal,” Kamat said. “That is the kind of number that, in any other context, would already be driving clinical guidelines.”

Kamat and her team found even higher cancer risk reductions in specific cancers, including a 58% lower risk of endometrial cancer.

“Endometrial cancer is rising fastest in younger women, it is tightly linked to obesity, and we have almost nothing to offer for prevention,” Kamat explained. “A 58% reduction is extraordinary. If that holds up in prospective studies, it changes how we think about this disease entirely, and this finding provides a strong rationale for further mechanistic and clinical studies focused on endometrial cancer prevention and treatment.”

The most dramatic drops in risk, where this reduction was by 50% or more, also occurred in multiple myeloma, pancreatic cancer, and colorectal cancer, in addition to endometrial cancer.

“We are not ready to say these drugs prevent cancer — our study cannot prove causation. But we are ready to say this finding demands a serious answer. Given the rapidly increasing use of these medications, even a modest reduction in cancer incidence could have important public health implications.”
—Aparna Kamat, MD

When asked how GLP-1s might help lower obesity-related cancer risk, Kamat said it’s probably a combination of weight loss and other factors.

“Separating them is one of the most important questions in the field right now. We know GLP-1 receptors are expressed directly on certain cancer cells. That means the drug could be acting on the tumor itself, not just shrinking the patient,” she said.

“If that’s true, weight loss is not the whole story but weight loss is likely an important contributor because excess adiposity promotes chronic inflammation, hormonal dysregulation, insulin resistance, and other processes linked to cancer development. Determining the relative contribution of these mechanisms remains an important area of ​​ongoing research,” she explained.

David Greenberg, MD, FACP, section chief of Hematology/Oncology at Hackensack Meridian Jersey Shore University Medical Center in New Jersey, who was not involved in this study, commented that he was not surprised by this study’s results, as we’ve known for decades that lifestyle, obesity, and toxic exposures play a critical role in the development of cell mutation and cancer.

“My cardiology colleagues have promoted GLP-1 drugs for several years to potentially improve a patient’s overall health,” Greenberg told Medical News Today.

“We know these (GLP-1) drugs not only diminish appetite and aid weight loss, but they also likely affect cardiovascular health, improve insulin sensitivity, and thus decrease overall inflammation in the body. Anything that decreases inflammation likely also decreases a person’s overall cancer risk. So I believe other factors are at play besides losing weight.”
—David Greenberg, MD, FACP

MNT spoke with Lauren Carcas, MD, a medical oncologist with Miami Cancer Institute, part of Baptist Health South Florida, about this study’s findings, who commented that while they’re exciting, the data must be interpreted in context.

“The observational design of the study allows for potential confounding of results as it does not take into account socioeconomic status, physical activity levels, dietary quality, and health-seeking behavior from the persons evaluated,” Carcas, who was not involved in this study, explained.

“Additionally, the results have only a median two-year follow-up. Most obesity associated cancers have a longer latency, meaning that the recurrence of their disease may not occur within the time frame evaluated,” she added.

Anton Bilchik, MD, PhD, surgical oncologist, chief of medicine, and director of the Gastrointestinal and Hepatobiliary Program at Providence Saint John’s Cancer Institute in Santa Monica, CA, who was also not involved in this study, agreed.

“Obesity is a well-established risk factor for numerous cancers, including colorectal, pancreatic, liver, uterine, ovarian, and breast cancers,” Bilchik detailed.

“It is therefore reasonable to hypothesize that sustained weight loss could reduce cancer risk. While findings from this new study are encouraging, more robust and long-term research is needed before physicians can confidently prescribe GLP-1 medications to non-diabetic patients with obesity specifically for cancer risk reduction,” he said.