Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine tumors (NETs) represent a heterogeneous group of neoplasms with diverse biological and clinical behavior, and gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are the most common subtype. This review provides an overview of GEP-NETs, with a focus on incidence trends, pathologic classification, diagnostic strategies, therapeutic advances, and the role of endoscopy in diagnosis and management of GEP-NETs. Incidence rates of GEP-NETs have significantly increased over recent decades, largely due to improved diagnostic modalities and increased use of endoscopy, although environmental factors may be at play as well. Pathologic grading and classification, based on the 2022 World Health Organization criteria, remain essential in defining prognosis and therapeutic options, and advanced imaging modalities like somatostatin receptor positron emission tomography scans enable precise localization and staging. Therapeutic approaches vary by tumor grade, stage, and localization, from an increasing role for endoscopic management of indolent tumors to surgical resection for certain higher-risk subtypes and for resectable metastatic disease. Novel treatments, including somatostatin analogs, radioligand therapy, mammalian target of rapamycin inhibitors, and antiangiogenic agents, have shown significant efficacy in advanced and metastatic disease. Future research is needed to identify molecular markers to refine diagnostic accuracy and personalize treatment strategies, thereby improving long-term outcomes for GEP-NET patients. Additionally, research is needed to better define GEP-NET subtypes that are appropriate for endoscopic therapy as well as to understand long-term outcomes after endoscopic resection. Given the important role that endoscopy has in the diagnosis and management of GEP-NETs, increased recognition of and knowledge about these tumors is critical for the gastroenterology community.