Importance of surgery in distant metastatic pancreatic neuroendocrine neoplasms

The majority of patients with pancreatic neuroendocrine neoplasms (pNEN) already present with distant metastases at diagnosis. The heterogeneity of pNEN and the broad spectrum of treatment options make adequate patient selection and an evidence-based strategy essential. In metastatic pNEN both primary resection and resection of liver metastases have been shown to improve overall survival. Surgical treatment of liver metastases can also be carried out with palliative intent, especially for symptomatic pNEN and can have a positive effect on disease-free survival and overall survival. Classical hepatectomy techniques and innovative techniques (two-stage resections, liver transplantation) are available to the surgeon. In complex growth types of liver metastases, there is increasing evidence for a combination of surgery and ablative methods. Due to a relevant risk of recurrence following liver resection, pNEN patients need to be included in multimodal treatment concepts. Current areas of interest in the treatment of metastatic pNEN are the use of adjuvant/neoadjuvant chemotherapy and surgery in G3-NEN and G3-NEC patients. The aim of this review is to give an overview on the impact of surgery in the situation of distant metastatic NEN of the pancreas.