Diagnostic Features and Management Options for Duodenal Neuroendocrine Neoplasms: A retrospective, Multi-Centre Study

Background: Duodenal neuroendocrine neoplasms (dNENs) are rare neoplasms but their incidence is on the rise. They are classified into 5 sub-types but there remains much heterogeneity in behaviour in particular of non-functioning dNENs. Aim: To retrospectively analyse outcomes for all types of dNENs, and highlight prognostic factors associated with worse outcome Results: 102 (57m/45f) patients were identified with mean age at diagnosis 62 (range 32-87) years. The majority were non-functioning tumours 87/102 and median size was 10mm (range 0.9-130mm). 83 patients had Stage I or II disease, of which 17 underwent endoscopic resection with R1 rate of 45% and complication rate 12%. 36 patients were kept under endoscopic surveillance. There were 11 deaths of which 4 were disease related. Age and Ki67 > 20% were associated with worse OS in all dNENs. In non-functioning dNENs Ki67 >3% was a predictor of lymph nodes metastases with OR 18.2 (2.54-13)(p < 0.005) in univariate analyses and liver metastases with OR 6.79 (1.56-29.5)( p < 0.05) in the multivariate analysis. Lesions 11 - 20 mm in size had OR 11.1 (1.16-106) compared to lesions <11mm for the prediction of lymph node metastases in the multivariate analysis (p < 0.05). ROC analysis of size of non-functioning dNENs to predict LN metastases found <15mm had an AUROC of 0.9 (0.81-0.99) with a sensitivity of 85% and specificity of 88%. Conclusion: dNENs are increasing in incidence, however low grade and smaller lesions have an indolent course and the role of endoscopic resection and active surveillance needs to be reviewed.