Increased screening may lead to higher thyroid cancer risk after GLP-1 initiation
Key takeaways:
- The risk for thyroid cancer within the first year of follow-up was higher with GLP-1 therapy vs. other diabetes drugs.
- Researchers attributed the higher thyroid cancer risk with GLP-1s to increased screening.
Adults with type 2 diabetes using a GLP-1 drug have a similar risk for thyroid cancer as those using other diabetes drugs, though increased thyroid cancer risk was observed in the first year after GLP-1 initiation, researchers reported.
In an analysis of administrative claims data from the OptumLabs Data Warehouse published in JAMA Otolaryngology–Head & Neck Surgery, researchers found the absolute risk for thyroid cancer with GLP-1 medication use was low, with less than 70 adults of 41,112 of those initiating GLP-1 therapy developing thyroid cancer. The risk for thyroid cancer over a maximum of 8 years of follow-up did not differ between GLP-1 medication users and adults using an SGLT2 inhibitor, DPP-IV inhibitor or sulfonylurea, though GLP-1 users did have a higher thyroid cancer risk during the first year of therapy. Rozalina G. McCoy, MD, MS, associate professor of medicine in the University of Maryland School of Medicine and director of the center for population health in the University of Maryland Institute for Health Computing, said the increased risk early during therapy is likely due to health care professionals being more vigilant with thyroid cancer screening when a person starts GLP-1 therapy.
“Patients treated with GLP-1 receptor agonists are not more likely to develop thyroid cancer, they are just more likely to be diagnosed with thyroid cancer because we (as clinicians) are more likely to look for it,” McCoy told Healio.
The cohort included 351,913 adults aged 21 years and older with type 2 diabetes and moderate risk for CVD who filled an initial prescription for a GLP-1 drug , SGLT2 inhibitor, DPP-IV inhibitor or sulfonylurea from 2014 to 2021 (mean age, 65.3 years; 49.3% women). The median follow-up was 1.8 years in the GLP-1 group and approximately 3.3 years in the other groups.
Compared with those using any non-GLP-1 medication, adults using a GLP-1 did not have a significant difference in thyroid cancer risk (HR = 1.24; 95% CI, 0.88-1.76) during the study period. The risk for thyroid cancer was also similar when GLP-1 users were compared with adults starting DPP-IV therapy (HR = 1.12; 95% CI, 0.77-1.63), a sulfonylurea (HR = 1.32; 95% CI, 0.92-1.88) or an SGLT2 inhibitor (HR = 1.16; 95% CI, 0.76-1.76).
During the first year after medication initiation, adults who started GLP-1 therapy had a higher thyroid cancer risk than those who started any non-GLP-1 drug (HR = 1.85; 95% CI, 1.11-3.08). A higher thyroid cancer risk within the first year of a first prescription fill was observed among GLP-1 users compared with adults who began a sulfonylurea (HR = 1.75; 95% CI, 1.04-2.97) or SGLT2 inhibitor (HR = 3.3; 95% CI, 1.74-6.22).
The researchers noted the higher thyroid cancer risk in the first year of follow-up might be attributed to more thyroid ultrasounds being performed among GLP-1 users. Of those who started GLP-1 therapy, 2.1% had a thyroid ultrasound performed at 1 year compared with 1.5% of those using a non-GLP-1 medication.
“We start looking for [thyroid cancer] because of the black box label on the drugs and the fear of medullary thyroid cancer, despite the fact that this fear is not grounded in strong evidence,” McCoy said. “So, either patients notice something in the neck, or we start doing neck exams after patients start treatment with a GLP-1, but we end up getting an ultrasound and finding low-risk thyroid cancers. We know that patients who are treated with GLP-1RA are much less likely to die from any cause than patients treated with DPP-IV inhibitors and sulfonylureas. ... So, we are finding low-risk thyroid cancers that likely would have never caused our patients any problems. This is what we have been seeing increasingly in the past decades with rapid increases in the rates of low-risk thyroid cancer diagnoses resulting from better imaging.”
McCoy noted the study did not include people with thyroid cancer and more research is needed to assess the effects of GLP-1s in people with benign thyroid nodules and those with either prior thyroid cancer or a family history of thyroid cancer.
For more information:
Rozalina G. McCoy, MD, MS, can be reached at rozalina.mccoy@som.umaryland.edu.
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