Effect of GLP-1 receptor agonists on patients with thyroid carcinomas undergoing active surveillance

Context Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as effective therapies for diabetes mellitus and obesity. Their effect on non-medullary thyroid malignancies remains unclear. Objective To evaluate the impact of GLP-1RA exposure on tumor kinetics of patients with low-risk papillary thyroid carcinoma (PTC) undergoing active surveillance (AS). Design Retrospective observational cohort study of 18 patients with 19 papillary thyroid carcinomas (≤1.5 cm) exposed to GLP-1RA matched 1:2 by BMI and tumor size to 37 patients with 38 carcinomas never exposed to GLP-1RA and undergoing AS at a single tertiary center for a median of 5.5 years. Main outcome Tumor growth/shrinkage was considered significant when any diameter changed by ≥3 mm and/or volume changed >72%. Tumor volume doubling time was calculated in a subset of patients off and on GLP-1RA therapy. Results After a median GLP-1RA exposure of 25 months [IQR: 14–34] and a median follow-up of 5.5 years, 2/19 (10.5%) tumors exposed to GLP-1RA exhibited significant volume growth, 1 (5.3%) decreased, and 16 (84.2%) remained stable, whereas 1/38 (2.6%) carcinoma not exposed to GLP-1RA showed >72% volume increase, 2/38 (5.3%) decreased and 35/38 (92.1%) remained stable, p=0.53. GLP-1RA exposure did not alter tumor volume growth kinetics in either of the two tumors that increased over time. Conclusions GLP-1RA therapy does not affect tumor growth kinetics in patients with low-risk PTC on AS. Further studies with larger cohorts and extended follow-up are warranted to validate the safety of GLP-1RA use in patients with thyroid carcinomas undergoing active surveillance.