Supplementary Material for: The Characteristics and Treatment Outcomes of 71 Duodenal Brunner’s gland Adenomas with Endoscopic Submucosal Dissection

Abstract Background: The aim of this study was to investigate outcomes of patients with duodenal Brunner’s gland adenomas (BGAs) that were treated endoscopically. Methods: We identified consecutive 71 patients treated at our center with endoscopic submucosal dissection (ESD) for their duodenal tumors diagnosed pathologically as BGAs over the period between January 1, 2011 and December 31, 2021. We retrospectively analyzed our experience and short- and long-term outcomes of ESD therapy on patients with BGAs. Results: Among 71 BGA patients with an average age of 57 ± 11.7 years (range: 30-82), 48 (67.6%) were male and 23 (32.4%) were female. The accuracy of preoperative diagnosis with endoscopic ultrasonography was 44.0% (22/50). The H. pylori infection was found in 29 patients (29/71, 40.8%). The median size of BGAs was 1.5 cm [interquartile range (IQR) 0.8-2.7cm]. The most common location was the duodenum bulb (50/71, 64.8%). For the ESD procedure, the median operation time was 15.0 minutes (IQR 9.5-25.5 minutes). The en-bloc and the complete resection rates were 97.2% and 92.3%, respectively. ESD-related mild acute obstructive pancreatitis was present in two patients (2/4, 50%) with BGAs located in the ampulla region. During the follow-up period, one patient with a positive peripheral margin experienced tumor recurrence 2 years after the initial ESD. There was no disease-related death for the cohort. Conclusion: ESD was an effective and safe therapeutic option for BGA patients with excellent outcomes. Long-term follow-up is needed.