New research has indicated increased risks of thyroid cancer for patients receiving glucagon-like peptide-1 receptor agonists (GLP-1 R A) during the first year of treatment. The study, published online on January 23, 2025, in JAMA Otolaryngology-Head & Neck Surgery, highlights important findings about thyroid cancer incidence for adults with type 2 diabetes.
Dr. Juan P. Brito and his team at the Mayo Clinic, located in Rochester, Minnesota, undertook this significant analysis to assess the risks associated with GLP-1 R A therapy compared to other widely used diabetes medications. The study included substantial patient cohorts, with 41,112 individuals starting treatment with GLP-1 R A, alongside 76,093 on dipeptidyl peptidase-4 inhibitors (DPP-4i), 43,499 on sodium-glucose cotransporter 2 inhibitors (SGLT2i), and 191,209 individuals initiating sulfonylurea therapy.
Across all patient groups, the absolute risk for developing thyroid cancer remained relatively low. The research revealed the incidence rates were 0.17% among those on GLP-1 R A, 0.23% for patients on DPP-4i, 0.17% for the SGLT2i cohort, and 0.20% for those on sulfonylureas.
According to their analyses, the initiation of GLP-1 R A therapy was not significantly associated with increased overall thyroid cancer risk compared to the other diabetes drugs studied. Specifically, the hazard ratio was calculated at 1.24 (95% confidence interval of 0.88 to 1.76), indicating no significant elevation risk across the broader treatment population.
Nevertheless, the study did find elevated risks of thyroid cancer during the first year of GLP-1 R A therapy. This point is particularly noteworthy: the hazard ratio for thyroid cancer risk right after initiating GLP-1 R A was 1.85 (95% CI, 1.11 to 3.08). This risk heightened even more when evaluating the data under strict treatment adherence conditions, reaching a hazard ratio of 2.07 (95% CI, 1.10 to 3.95).
Dr. Brito emphasized the implication of these findings, stating, "These findings indicate GLP-1 R A initiation was associated with new diagnosis of thyroid cancer only in the short term, likely due to increased vigilance and case detection rather than de novo pathogenesis." This suggests the observed increase might not directly relate to the medication's pathological effects but could rather stem from close monitoring and heightened detection practices among patients during the initial treatment phases.
Overall, the study has drawn attention to the nuanced relationship between GLP-1 R A treatment and thyroid cancer risk, particularly highlighting the significance of patient monitoring during the early stages of therapy. With increasing use of GLP-1 R A therapy, these insights are pertinent for healthcare providers managing patients with type 2 diabetes.