Middle aged man with type 2 diabetes using blood sugar measurement device to monitor type 2 diabetes, which can be linked to changes in the gut microbiome.
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A study of more than 1.5 million people with type 2 diabetes has shown that individuals using glucagon-like peptide 1 receptor agonists (GLP-1 RAs) have a significantly lower risk for obesity-associated cancers (OACs) than those using insulin.

The findings “provide preliminary evidence of the potential benefit of GLP-1 RAs for cancer prevention in high-risk populations,” write Lindsey Wang, from Case Western Reserve University School of Medicine in Cleveland, Ohio, and co-authors in JAMA Network Open.

They explain that there are 13 malignant neoplasms that have been identified as OACs, meaning that the presence of excess body fat is associated with an increased risk for developing these cancers and with a worse prognosis once the cancer is diagnosed. Obesity also contributes to insulin resistance and type 2 diabetes, which may further increase the risk and worsen the prognosis of the OACs.

Since GLP-1 RAs are highly effective in the treatment of diabetes and for achieving weight loss, Wang and team hypothesized that these agents might reduce the risk for OACs.

To investigate, they reviewed electronic health record data for 1,651,452 U.S. patients with type 2 diabetes who had no history of OACs and were prescribed GLP-1RAs, insulins, or metformin between 2005 and 2018.

During a 15-year follow-up period, the researchers found that the 48,983 individuals prescribed a GLP-1 RA and no insulin had a significantly lower risk for 10 of the 13 OACs than the 1,097,728 propensity-score matched individuals prescribed insulin and no GLP-1 RA.

Specifically, the risks for gallbladder cancer, meningioma, and pancreatic cancer were 65%, 63%, and 59% lower, respectively, in people given a GLP-1 RA than in those given insulin.

For hepatocellular carcinoma, ovarian cancer, and colorectal cancer, the risk reductions were a respective 53%, 48%, and 46%, while for multiple myeloma, esophageal cancer, endometrial cancer, and kidney cancer, the risks were 41%, 40%, 26%, and 24% lower, respectively, with GLP-1 RAs than with insulin.

People using GLP-1 RAs also had a statistically non-significant 27% lower risk for stomach cancer than those who took insulin, and there was no difference in risk between the two treatments for the remaining two OACs, namely postmenopausal breast cancer and thyroid cancer.

Wang and her team also compared OAC incidence between GLP-1 RA users and metformin users and generally found that the risk was similar between the two groups. The only exceptions were statistically non-significant 63% and 46% lower risks for gallbladder cancer and meningioma, respectively, with GLP-1 RAs versus metformin, and a significant 54% higher risk for kidney cancer in the GLP-1 RA group.

The authors note that, to their knowledge, kidney cancer has not previously been associated with GLP-1 RA use and suggest the finding warrants further investigation.

They also say that it will be important understand how their findings correlate with the control of type 2 diabetes and obesity, evaluate the effects of GLP-1 RAs on non-OACs, and study the impact of newer and possibly more effective antidiabetic and weight loss agents on OACs.

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