Clinical and long-term oncological outcomes of gastroduodenal neuroendocrine neoplasms after endoscopic resection - a Multinational Western study

Abstract

Objective: Gastroduodenal neuroendocrine neoplasms (GD-NENs) are being increasingly diagnosed, particularly at stages amenable to endoscopic resection (ER). We aimed to evaluate endoscopic, long-term clinical and oncological outcomes of patients with GD-NENs submitted to ER. Material and methods: Multinational retrospective study (24 centres, 10 Western countries) that analysed all patients who underwent ER of GD-NENs (January 2014-December 2024). Demographic, clinicopathological and long-term oncological data were collected. A curative resection was defined according to the ENETS guidelines (2023). The cohort was divided in two groups considering the procedure date (2014-2018; 2019-2024) for comparison. Results: We evaluated 446 patients: 304 gastric (G-NENs) (74.7% type 1) and 142 duodenal (D-NENs). The median lesion size was 10 mm (IQR 6-12). Endoscopic submucosal dissection (ESD) (32.7%) and conventional endoscopic mucosal resection (C-EMR) (26.5%) were the most performed techniques. G-NENs had significantly higher R0 rates (59.8%; 42.3% D-NENs; p<0.001). Non-curative ER rate was 58.3% (51.0% G-NENs; 73.9% D-NENs; p<0.001). Median follow-up was 37 months (IQR 14-70). Local and distant recurrence rate were 13.2% (14.8% G-NENs; 9.9% D-NENs; p=0.109) and 1.8% (1.3% G-NENs; 2.8% D-NENs; p=0.266), respectively. Group 2 had a decrease in ESD (37.2%, 29.7%) and increase of band ligation EMR (8.3%, 21.4%) and endoscopic full-thickness resection (1.1%, 5.6%). Group 2 had significantly higher curative resection rates (46.6%; 34.4%; p=0.011). Conclusion: The recurrence of GD-NENs submitted to ER is low, despite suboptimal curative resection rates. The increased curative resection rate in most recent procedures showcases the possibility to optimize patient selection and lesion endoscopic management.