Extrahepatic biliary neuroendocrine tumors: A national cancer database analysis.

ABSTRACT

Background: Extrahepatic biliary neuroendocrine tumors (EBNETs) are rare. We aimed to characterize EBNETs including factors associated with survival. Methods: The National Cancer Database was queried for patients with EBNETs from 2004 to 2016. Patients who underwent resection were examined using Cox proportional hazards regression and the Kaplan-Meier method. We compared overall survival (OS) among patients with EBNETs to those with NETs from other primary sites. Results: Overall, 223 patients with EBNETs were identified. Patients were predominantly male (n = 113, 50.7 %), white (n = 177, 79.4 %) and presented without distant metastasis (n = 182, 81.6 %). The majority underwent operation (n = 127, 57.9 %) with resection of the primary tumor (n = 89, 70 %). Among patients who underwent resection (n = 71), multivariable regression demonstrated older age (HR 1.11, 95 % C.I. 1.04-1.17), lymph node metastases (HR 1.19, 95 % C.I. 1.02-1.38) and poorly/undifferentiated tumors [HR 22.3, 95 % C.I. 3.78-131]) were associated with worse overall survival. Patients with EBNETs experienced abbreviated OS compared to patients with small bowel or pancreas NETs (p < 0.001), but improved OS when compared to patients with gallbladder NETs (p = 0.001). Conclusions: Tumor differentiation and lymph node status significantly impact overall survival.