Resection of primary tumor may prolong survival in metastatic gastroenteropancreatic neuroendocrine tumors

Background: Patients with gastroenteropancreatic neuroendocrine tumors often present with stage IV disease. Primary tumor resection in these patients remains controversial. Herein, we studied the impact of primary tumor removal, identified variables associated with prolonged survival for each neuroendocrine tumor subtype, and determined factors that influence surgeons to perform primary tumor resection. Methods: Patients with metastatic gastroenteropancreatic neuroendocrine tumors diagnosed from 2004 to 2014 were identified from the National Cancer Database. Nested Cox proportional hazards and logistic regression models were used to assess variables associated with survival and primary resection. Results: A total of 14,510 patients met inclusion criteria. On multivariable analysis, resection of the primary tumor and grade 1 or 2 tumors was associated with prolonged survival in all subtypes (P < .001). Organ-specific variables associated with prolonged survival in patients undergoing primary tumor resection included the following: low grade for all organs; young age for pancreatic, small intestinal, colonic, and rectal neuroendocrine tumor; tumor size for colonic and rectal neuroendocrine tumor; and tumor location for colonic neuroendocrine tumor. Low tumor grade was found to be significantly associated with removal of the primary tumor across all organs. Conclusion: This study is the first suggesting that primary tumor resection is associated with prolonged survival for all gastro-entero-pancreatic NETs. Additional variables related to survival for each NET subtype were identified and might help select patients who benefit from primary tumor removal. (C) 2018 Elsevier Inc. All rights reserved.