Surgical treatment of gastroentero-pancreatic neuroendocrine tumor

The treatment of choice for gastroentero-pancreatic neuroendocrine tumor (NET) is resection. Because it is difficult to determine the histological grade of NET before operation, the treatment strategy is usually made based on an imaging study including the tumor's size. Some selected gastrointestinal NETs are indicated for endoscopic resection, while others are resected surgically with lymph node dissection. The types of resections for pancreatic NETs vary from enucleation to pancreatectomy with or without regional lymph node dissection, based on the type of excessive hormone, tumor size, distance from the main pancreatic duct, and the presence of type 1 multiple endocrine neoplasia. Hepatic metastases are also resected, if indicated, and even in patients having unresectable metastatic lesions, multidisciplinary therapy including reduction surgery of over 90% of tumor volume might lead to a favorable prognosis. Postoperative adjuvant therapy is recommended for neuroendocrine carcinoma, while there is no evidence to support adjuvant therapy for curatively resected well-differentiated NET.