GLP-1 Agonists: Theoretical Risks for Neuroendocrine Tumors

In an interview with Targeted Oncology, Joseph Dillon, MB, BCh, BAO, professor of Internal Medicine (Endocrinology and Metabolism) at Carver College of Medicine at the University of Iowa, discusses the necessary considerations for integrating glucagon-like peptide-1 (GLP-1) receptor agonists in patient care, the topic of his presentation during the 2025 North American Neuroendocrine Tumor Society (NANETS) Multidisciplinary NET Medical Symposium. In this discussion, he focused on potential safety risks for patients with neuroendocrine tumors (NETs).

Read the full interview here.

The clinical use of GLP-1 receptor agonists, widely approved for conditions like diabetes and obesity, is rapidly expanding. Dillon noted that in clinical practice, approximately 6% of patients in a NET clinic are taking these drugs, reflecting the usage rate in the general US adult population due to the high nationwide prevalence of both type 2 diabetes and obesity.

While there have been no specific reports detailing a direct impact of GLP-1 agents on NET patients to date, theoretical concerns exist, stemming from preclinical evidence showing that a proportion of NETs have receptors for GLP-like molecules. Studies conducted in animals and in vitro demonstrate that when GLP is added to tumors expressing these receptors, the tumors will grow. Although the clinical relevance of these findings remain unclear, the evidence highlights a concerning potential for tumor growth in certain patients with NETs, warranting future clinical investigation.

Key research gaps and areas of investigation, according to Dillon, include identifying which patients’ NETs express the GLP receptor, as well as conducting clinical trials to determine whether GLP-1s and related agents have a significant effect on the growth of NETs in humans.