From the Guidelines
When considering GLP-1 receptor agonists for patients with both thyroid cancer and type 2 diabetes, caution is warranted but these medications are not absolutely contraindicated, as the most recent evidence from 2024 suggests that GLP1 agonists reduce all-cause mortality and major adverse cardiovascular events (MACE) compared with usual care 1. The primary concern stems from animal studies showing an increased risk of medullary thyroid carcinoma with these medications, particularly in rodents, as noted in the 2019 American Heart Association statement 1. However, this risk has not been definitively established in humans. For patients with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2, these medications are contraindicated, as stated in the FDA Black Box Warning for GLP-1 receptor agonists 1. For patients with other types of thyroid cancer, such as papillary or follicular thyroid cancer, the decision should be individualized based on cancer status, diabetes control needs, and risk-benefit assessment. Some key points to consider when using GLP-1 receptor agonists in these patients include:
- Regular thyroid monitoring is recommended, including physical examinations and possibly thyroid function tests or ultrasounds as determined by the patient's endocrinologist.
- The benefits of improved glycemic control, weight reduction, and potential cardiovascular benefits must be weighed against the theoretical thyroid risk for each patient.
- Semaglutide (Ozempic, Wegovy), liraglutide (Victoza, Saxenda), dulaglutide (Trulicity), and tirzepatide (Mounjaro) should be used with careful monitoring in these patients. The most recent and highest quality study, a systematic review and network meta-analysis published in 2024, supports the use of GLP1 agonists in patients with type 2 diabetes, including those with thyroid cancer, due to their benefits in reducing all-cause mortality and MACE 1.
From the FDA Drug Label
Neoplasms: Medullary thyroid carcinoma The FDA drug label mentions medullary thyroid carcinoma as a potential adverse reaction, but it does not provide specific guidance on the use of GLP-1 receptor agonists in patients with thyroid cancer and type 2 diabetes.
- Key Considerations:
- Medullary thyroid carcinoma has been reported in postmarketing experience with liraglutide injection.
- The clinical significance of elevated calcitonin levels is unknown.
- Patients with a history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2 should be advised of the potential risk of GLP-1 receptor agonists 2. However, the label does not provide direct information to answer the question. The FDA drug label does not answer the question.
From the Research
Considerations for Using GLP-1 Receptor Agonists in Patients with Thyroid Cancer and Type 2 Diabetes
- The use of glucagon-like peptide-1 (GLP-1) receptor agonists in patients with type 2 diabetes and thyroid cancer has been a topic of interest due to potential associations between GLP-1 receptor agonists and thyroid cancer risk 3, 4, 5, 6, 7.
- A study published in JAMA Otolaryngology--Head & Neck Surgery found that GLP-1 receptor agonist initiation was not significantly associated with increased overall risk for thyroid cancer compared to other diabetes drugs, but the risk for thyroid cancer was significantly higher within the first year after GLP-1 receptor agonist initiation 3.
- Another study published in Diabetes Care found that use of GLP-1 receptor agonists for 1-3 years was associated with increased risk of all thyroid cancer and medullary thyroid cancer 4.
- However, a multisite cohort study published in Thyroid found no evidence that GLP-1 receptor agonist use is associated with an increased risk of thyroid cancer with follow-up ranging from 1.8 to 3.0 years 5.
- A population-based cohort study published in Diabetes, Obesity & Metabolism found that the use of GLP-1 receptor agonists was not associated with an increased risk of thyroid cancer compared with sodium-glucose cotransporter-2 inhibitors 6.
- A retrospective cohort study published in Diabetes Care found that GLP-1 receptor agonist exposure was not associated with an increased risk of thyroid tumors compared with sodium-glucose cotransporter-2 inhibitors, dipeptidyl peptidase-4 inhibitors, or sulfonylureas 7.
Key Findings
- The association between GLP-1 receptor agonists and thyroid cancer risk is still unclear and requires further research 3, 4, 5, 6, 7.
- Some studies suggest a potential increased risk of thyroid cancer with GLP-1 receptor agonist use, particularly within the first year of initiation or with cumulative use of 1-3 years 3, 4.
- Other studies found no significant association between GLP-1 receptor agonist use and thyroid cancer risk 5, 6, 7.
- The evidence suggests that the risk of thyroid cancer with GLP-1 receptor agonist use may be low, but further research is needed to fully understand the association 3, 4, 5, 6, 7.