Ozempic and Thyroid Cancer: What a Thyroid Surgeon Wants you to Know

Because thyroid problems are associated with weight gain, it is very common for patients to be searching for ways to lose weight. One of the most effective methods is to use GLP-1 agonists such as Ozempic, Wegovy, Mounjaro, etc to help. But if you have thyroid problems, should you be worried that these GLP-1s would cause thyroid cancer?

First, let's talk about how these drugs like Ozempic work, and why GLP1s might be associated with thyroid cancer. These drugs will act similar to natural hormones in your body (known as GLP-1), increasing insulin secretion and also slowing gastric motility. They therefore would lower your blood sugar and make you feel more full, leading to more weight loss. This is all fantastic, and overall seems to lead to improvements in a wide range of other health problems that are exacerbated by being overweight. One of the things that I have noticed is that people seem to have less inflammation when they are taking these drugs, which is very important with autoimmune diseases that often attack the thyroid such as Hashimoto's thyroiditis and even Graves' disease.

These drugs ARE associated with thyroid cancer, but only a very rare form of thyroid cancer. In some early studies at very high doses, some rats developed a rare form of thyroid cancer called Medullary Thyroid Cancer. This has caused many people with thyroid nodules or thyroid diseases to wonder if they should avoid GLP1s because they might cause thyroid cancer. The good news is that these risks have so far not been demonstrated in human studies, and so most of us who treat thyroid cancer think that there is little risk of these drugs causing thyroid cancer in humans when taken at normal doses.

What about patients who have Hashimoto's thyroiditis or Graves' disease? Are they at an increased risk because both of those conditions are associated with thyroid cancer, and so maybe taking Mounjaro would cause thyroid cancer for these people at an increased risk? The good news seems to be that this is not the case. Even in these patients at higher risk, the risk of thyroid cancer seems to be similar to the risk of thyroid cancer in the general population.

There are some studies that have demonstrated an increased risk in patients taking GLP1s, so why don't doctors talk about those? I don't worry too much about those studies because when you dig into the studies, it seems that most of the difference in cancer rates between the groups comes from differences in FINDING cancer, not differences in growing cancer. What does that mean? It seems to mean that, because Ozempic patients are worried about thyroid cancer, they are more likely to check the thyroid for cancer. And if you check the thyroid for cancer, you are more likely to find it. And so it is possible and likely that we are finding cancers earlier when people are on Wegovy, which artificially makes it seem like these patients have more thyroid cancer. In other words, the Ozempic doesn't CAUSE the thyroid cancer, but it helps us to look for it, and when we look, we find it in some people.

I'm a thyroid cancer surgeon, and even more than that, I'm part of the American Thyroid Association Guidelines and Statement committee. In this role, I help to develop the new guidelines that are coming out from the world's leading authority on thyroid disease. We talk about thyroid cancer and new drugs all the time. In other words, I read lots of scientific articles and work with some really smart people! Collectively, this information has led me to believe that these drugs are safe for most patients, even for patients who have thyroid conditions. And that Mounjaro is unlike to cause thyroid cancer for most patients.

In fact, there are some of my patients with thyroid cancer who I encourage to stay on GLP1s because I believe the benefits outweigh the risks. Why would I say this? Because obesity is also associated with thyroid cancer, and even more aggressive thyroid cancer! So by losing weight, patients might be decreasing their risk of thyroid cancer. Additionally, reducing inflammation can help conditions like Hashimoto's and Graves' disease. Which can theoretically help those patients to decrease their risk of thyroid cancer! For other patients, we will combine this with a scarless thyroid surgery or another technique that helps to reduce antibodies and inflammation and gets them back to normal, faster.

Who should avoid these drugs? Talk to your doctor! Every situation is unique. But patients who have a personal or family history of Medullary Thyroid Carcinoma (MTC) should be cautious and likely avoid them.

This is what we do at the Russell Center: we weigh the pros and cons of lots of information and ideas and look for the solution that is best for you. It's not a one-size fits all approach, but instead a thoughtful solution that is personalized to you. For most of my patients, that means that I tell them to stick to their GLP1s, lose some weight, and realize that the lost weight is probably healthy for them- and even healthy for their thyroid!