GLP-1 Medications and Thyroid Cancer Risk: What Patients Should Know

Dr. Samantha Newman, an endocrinologist at Memorial Sloan Kettering Cancer Center in New York City, tells SurvivorNet that much of that coverage — associating a link between GLP-1 drugs and thyroid cancer — has to do with a warning that affects very few patients.

“GLP-1s have gotten kind of a bad reputation for being associated with thyroid cancer based on some very early studies which showed an increased risk in medullary thyroid cancer in animal populations in very, very early trials,” Dr. Newman explains.

What Exactly Are GLP-1 Medications?

GLP-1 medications, also known as GLP-1 agonists, represent a class of injectable or oral medicines first developed to treat type 2 diabetes. They’re known for helping control blood sugar, supporting weight loss, and improving overall heart health. These medications mimic a hormone called GLP-1 (Glucagon-Like Peptide-1), naturally produced in our gut.

GLP-1 slows digestion, controls appetite, and stimulates insulin release after meals, all of which can greatly help patients struggling with diabetes and obesity.

“GLP-1s work fantastically. I mean, they’re really pretty remarkable. And individuals with obesity can be at risk for heart disease and other health problems,” Dr. Megan Haymart, a professor of medicine at the University of Michigan and an endocrinologist by training, tells SurvivorNet.

Due to the incredible results doctors have observed regarding weight loss, GLP-1 medications have become increasingly popular beyond just diabetes treatment.

For patients with thyroid cancer specifically, the drugs can also be beneficial.

“For my patients with papillary thyroid cancer who struggle with obesity or diabetes, I think the benefits of the GLP-1 are definitely there. There has not been clearly documented risk, and I think they should proceed with it,” she says. However, there is a specific subset of patients who the drugs are not recommended for right now — those with medullary thyroid cancer.

GLP-1 Drugs & Thyroid Cancer: The Concerns

There have been some warnings about possible risks of patients with thyroid cancer using GLP-1 medications.

In animal studies (specifically in rodents), GLP-1 medications were associated with an increased risk of a rare type of thyroid cancer known as medullary thyroid carcinoma (MTC). Because of this concern, these medications carry a Food and Drug Administration (FDA) “black box” warning (the strongest alert given by the FDA) cautioning against their use in people with a personal or family history of MTC or a rare genetic condition called Multiple Endocrine Neoplasia syndrome type 2 (MEN2).

“If a patient has medullary thyroid cancer or family history of medullary thyroid cancer or MEN2, which is a syndrome that has medullary thyroid cancer in it, right now, we don’t recommend that they’re on GLP-1. But that’s my patients with medullary thyroid cancer, which is like 5 to 10% of my patients,” says Dr. Haymart.

However — and this is a critical distinction — no human studies have precisely shown that these medications cause medullary thyroid cancer or significantly increase the risk of developing it. Still, doctors recommend caution because of these animal studies, and the possibility, however small, warrants careful consideration.

What About Papillary & Follicular Thyroid Cancers?

“An overwhelming majority of thyroid cancers aren’t medullary thyroid cancers,” Dr. Newman explains. “…The vast majority are either papillary or follicular thyroid cancers and in those, there has been no association ever with any increased risk of thyroid cancer with GLP-1 drugs.”

If your diagnosis is papillary or follicular thyroid cancer, which together represent the vast majority of thyroid cancers, there’s reassuring news. According to medical experts, there’s no warning against using GLP-1 medications for these types of thyroid cancer.

“The recent studies that have looked at this, looking at all thyroid cancers; it appears that there’s not a real risk … there may in fact be some screening bias, but no clear evidence that it’s actually causing thyroid cancer,” Dr. Haymart adds.

In fact, these more common thyroid cancers (papillary, follicular, or even anaplastic) are originally different from medullary thyroid carcinoma, meaning the risks observed in animal studies don’t translate directly to these other types of thyroid cancer.

What Type Of GLP-1 Medication To Consider

Patients with non-medullary thyroid cancers who fight against obesity, prediabetes, type 2 diabetes, or cardiovascular disease could certainly benefit from GLP-1 therapies. Improved weight management and blood sugar control can lead to better overall health, reduced risk of cardiovascular complications, and an improved quality of life.

But, as with any medication, discussing potential risks and benefits with your healthcare provider is crucial. Your doctor can evaluate your individual health profile, including cancer history, treatment outcomes, and risk factors, to decide if GLP-1 medications are appropriate for you.

Questions To Ask Your Doctor

• Is GLP-1 medication safe for my type of thyroid cancer?
• Do I have any risk factors or family history that might affect my suitability for GLP-1 medications?
• How should we monitor my thyroid health if I start taking GLP-1 therapy?
• Are there alternative treatments that might be safer or more effective given my medical history?

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