A systematic review on endoscopic ultrasound in gastric neuroendocrine neoplasms: guidelines outpacing evidence

Background/aims: Gastric neuroendocrine neoplasms (g-NENs), though rare, have shown a rise in incidence due to increased endoscopic screening and improved diagnostic awareness. International guidelines recommend the use of endoscopic ultrasound (EUS) in managing g-NENs to evaluate subepithelial lesion size, depth, and lymph node involvement before endoscopic resection. However, the supporting evidence for EUS's role in g-NENs is scarce and limited. Methods: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a comprehensive literature search was conducted on PubMed to identify studies about the role of EUS in g-NENs, including both retrospective and prospective human studies. Results: A total of 355 studies were considered; however, only seven were included, highlighting EUS's diagnostic utility in g-NENs, with only 44 specific cases. EUS showed promise in assessing tumor characteristics critical for endoscopic resection. Nevertheless, its diagnostic accuracy remained variable across lesion types, and its impact on clinical decision-making in g-NENs lacked robust evidence. EUS contributed to subepithelial lesion staging but was underrepresented in neuroendocrine tumor-specific studies, creating a knowledge gap. Conclusions: This review underscores the need for larger multicenter studies to validate EUS's efficacy and reliability in g-NEN management. Prospective trials are crucial to strengthen guidelines and provide clearer clinical guidance for managing these tumors.