Comparison of Oncological and Surgical Outcomes Between Formal Pancreatic Resections and Parenchyma-Sparing Resections for Small PanNETs (<2 cm): Pancreas2000 Research and Educational Program (Course 9) Study Protocol.

Pancreatic neuroendocrine tumors (PanNETs) are rare tumors but incidence is increasing. An increasing number of these tumors are diagnosed incidentally when they are small (<2 cm) and when patients are asymptomatic. The European Neuroendocrine Tumor Society (ENETS) recommends conservative watch and wait policy for these patients. However, best surgical approach (parenchyma-sparing or formal oncological resection) for these small tumors when surgery is indicated is currently unknown. Parenchyma-sparing resections such as enucleation is associated with higher risk of post-operative morbidity compared to formal oncological resections. They are also be associated with potentially inadequate surgical margin clearance and with lack of lymphadenectomy for full pathological staging. This study is a retrospective study and the aim is to analyze pre-operative clinical predictors of nodal metastases for small PanNETs to identify which patients are at a lower risk of lymph node metastases and are therefore suitable for parenchyma-sparing resection. The primary endpoint of this study is to determine if pre-operative clinical predictors such as tumor size are associated with lymph node involvement in small PanNETs.