Supplementary Material for: Endoscopic and surgical management of non-metastatic ampullary neuroendocrine neoplasia: a multi-institutional Pancreas2000/EPC study

Introduction: Ampullary neuroendocrine neoplasia (NEN) are rare and evidence regarding their management is scarce. This study aimed to describe clinico-pathological features, management and prognosis of ampullary NEN according to their endoscopic or surgical management. Methods: From a multi-institutional international database patients treated with either endoscopic papillectomy (EP), transduodenal ampullectomy (TSA) or pancreatoduodenectomy (PD) for ampullary NEN were included. Clinical features, post procedure complications and recurrences were assessed. Results: 65 patients were included, 20 (30.8%) treated with EP, 19 (29.2%) with TSA and 26 (40%) with PD. Patients were mostly asymptomatic (n= 46; 70.8%). Median tumour size was 17 mm (12 – 22), tumors were mostly grade 1 (70.8%) and pT2 (55.4%). Two (10%) EP resulted in severe ASGE adverse post procedure complications and 10 (50%) were R0. Clavien III to V complications did not occur after TSA and in 4, including 1 postoperative death (15.4%) of patients after PD, with 17 (89.5%) and 26 R0-resection (100%) respectively. The pN1/2 rate was 51.9% (n= 14) after PD. Tumor size larger than 1 cm (i.e. pT stage >1) was a predictor for R1 resection (p<0.001). Three-year OS and DFS after EP, TSA and PD were 92%, 68%, 92% and 92%, 85%, 73%. Conclusion: Management of ampullary NEN is challenging. EP should not be performed in lesions larger than 1 cm or with a EUS-T-stage beyond T1. Local resection by TSA seems safe and feasible for lesions without nodal involvement. PD should be preferred for larger ampullary NEN at risk of nodal metastasis.