New Findings Suggest No Correlation Between GLP-1 Receptor Agonists and Thyroid Cancer Risk

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Glucagon-like peptide (GLP)-1 receptor agonists may not be associated with an increased risk of thyroid cancer, according to a recent study published by Pasternak et al in the BMJ.


GLP-1 receptor agonists are designed to reduce blood sugar levels and appetite. They have become increasingly popular to treat type 2 diabetes and obesity; however, prior research reporting adverse event data has suggested that these drugs could be associated with an increased risk of thyroid tumors. Because of limitations in data and methodology, clear conclusions could not be previously drawn, leading to uncertainty about this potential side effect.

“Many [patients] take these medicines, so it is important to study potential risks associated with them,” explained lead study author Björn Pasternak, MD, PhD, of the Department of Medicine, Solna at the Karolinska Institutet in Sweden.

Study Methods and Results

In the recent study, investigators used national register data from Denmark, Norway, and Sweden to analyze the outcomes of 145,000 patients who received GLP-1 receptor agonists—chiefly liraglutide and semaglutide—and 290,000 patients who received dipeptidyl peptidase (DPP)-4 inhibitors.

After a follow-up of just under 4 years, the investigators found that the risk of thyroid cancer was not increased in the GLP-1 receptor agonist group. The results were consistent when comparing them to the risk of thyroid cancer in patients who received sodium-glucose cotransporter-2 inhibitors.


“We cannot rule out that the risk of certain subtypes of thyroid cancer is increased in smaller patient groups that we could not study here, for example, in [patients] with a high congenital risk of medullary thyroid cancer who are advised against using these drugs,” emphasized senior study author Peter Ueda, MD, PhD, Assistant Professor in the Department of Medicine, Solna at the Karolinska Institutet.

The investigators plan to continue exploring the effects and potential side effects of newer diabetes drugs that are now being used to treat broader patient groups, including those with obesity, heart failure, and kidney failure.

“Our study covers a broad group of patients and provides strong support that GLP-1 [receptor agonists] are not associated with an increased risk of thyroid cancer,” Dr. Pasternak underscored. “We know from randomized clinical trials that they have positive effects, but clinical reality is different with patients varying in disease severity, comorbidities, and adherence to treatment recommendations. It’s therefore essential to investigate how these medicines perform in everyday clinical settings,” he concluded.

Disclosure: The research in this study was financed by the Swedish Cancer Society, the Swedish Research Council, and Karolinska Institutet. For full disclosures of the study authors, visit

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