Clinicopathological features and surgical outcomes of resected functional pancreatic neuroendocrine tumors: a single institution experience

Background: Functional pancreatic neuroendocrine tumors (f-PanNETs) are rare tumors of the pancreas that are associated with excess hormone production. A majority of literature available on these tumors is limited to case reports and small series and discusses a particular subtype. Here, we report the clinicopathological features and outcomes of all f-PanNETs from a high-volume pancreatectomy center. Methods: A prospectively maintained database was used to identify patients who underwent resection for f-PanNETs between January 1995 and December 2015. Patients were stratified by the type of f-PanNET, and their clinicopathological features and outcomes were analyzed and reported. Results: We identified 69 patients with a mean age of 52 ± 16 years, and the majority were female (62%). The most common type of f-PanNET were insulinomas (70%) followed by gastrinomas (15%), and vasoactive intestinal peptidomas (VIPomas) (10%). There was considerable heterogeneity in the presenting symptoms. Patients with insulinomas presented with smaller tumors compared to the other subtypes. Nodal disease was most frequent in patients with VIPomas (71 %), and gastrinomas (50%). The median overall survival (OS) was 7.4 years. Elevated Ki-67 and age >65 years were associated with poorer OS. Recurrence was observed in 8 patients (12%) and was most frequent in patients with VIPomas. Recurrence was associated with a poorer OS (P=.012). Conclusion: f-PanNETs are exceedingly rare and present with a wide variety of symptoms, histopathological findings, and outcomes. Surgical resection can help achieve good long-term survival. Key words: Functional tumor; Outcome; Pancreatic neuroendocrine tumor