Prognostic factors and characteristics of pancreatic neuroendocrine tumors : single center experience

Abstract

Purpose: Pancreatic neuroendocrine tumors (PNET) are a rare subgroup of tumors. For PNETs, predictive factors for survival and prognosis are not well known. The purpose of our study was to evaluate the predictive factors for survival and disease progression in PNETs. Material and Methods: We retrospectively analyze 37 patients who were diagnosed as PNET at Severance Hospital between November 2005 and March 2010. Prognostic factors for survival and disease progression were evaluated using the Kaplan-Meier method. Results: The mean age of the patients was 50.0±15.0 years. Eight cases (21.6%) were described as functioning tumors and 29 cases (78.4%) as non-functioning tumors. In univariate analysis of clinical factors, patients with liver metastasis (p=0.002), without resection of primary tumors (p=0.002), or AJCC/UICC III/IV stage (p=0.002) were more likely to show shorter overall survival (OS). Patients with bile duct or pancreatic duct invasion (p=0.031), larger than 20mm sized-lesions (p=0.036), liver metastasis (p=0.020), distant metastasis (p=0.005), lymph node metastasis (p=0.009) or without resection of primary tumors (p=0.020) were more likely to show shorter progression-free survival (PFS). In multivariate analysis of clinical factors, bile duct or pancreatic duct invasion [p=0.010, hazard ratio (HR) =95.046], and tumor location (non-head of pancreas) (p=0.036, HR=7.381) were confirmed as independent factors to predict shorter PFS. Conclusion: Patients with liver metastasis or without resection of primary tumors were more likely to show shorter OS. Patients with bile duct or pancreatic duct invasion or tumors located at body or tail of pancreas were more likely to show shorter PFS.