Role of Locoregional and Systemic Approaches for the Treatment of Patients with Metastatic Neuroendocrine Tumors.

Although gastroenteropancreatic neuroendocrine tumors are often perceived as being indolent tumors, more than half of the patients will harbor liver metastases at the time of diagnosis. Gastroenteropancreatic neuroendocrine tumors have the potential to be aggressive and resistant to therapy, making the integration of both locoregional and systemic therapy even more critical in the treatment of patients with locally advanced or metastatic lesions. Over the last several years, significant advancements have been made in the surgical treatment, liver-directed therapy, and medical management of gastroenteropancreatic neuroendocrine tumors. While surgical resection is the cornerstone of therapy, cytoreductive surgery, orthotopic liver transplantation, local ablation, and intra-arterial therapy all improve the prognosis of patients suffering with locally advanced or metastatic disease. In addition, great strides have been made in the medical management of gastroenteropancreatic neuroendocrine tumors, particularly with the evolution of novel molecular targeted therapy, such as everolimus and sunitinib. Hence, gastroenteropancreatic neuroendocrine tumor is becoming a disease process requiring more of a multi-disciplinary approach with the integration of both locoregional and systemic therapies for improved outcomes.