Survival and prognostic factors analysis of 151 intestinal and pancreatic neuroendocrine tumors: a single center experience

Background: Intestinal and pancreatic neuroendocrine tumors (IP-NETs) are rare tumors with heterogeneous outcomes. The aim of our study was to determine the clinical, therapeutic and pathological factors which impact the overall survival (OS) in IP-NETs. Methods: All the patients diagnosed with IP-NETs at the Nantes University Hospital between October 1994 and October 2013 were retrospectively analysed. Patients with MEN-1 (Type 1 Multiple Endocrine Neoplasia) or Von Hippel-Lindau syndrome were excluded. Additionally, a prospective analysis of tumor grade (mitotic index and Ki67 index) was performed on tumor samples. OS was evaluated by Kaplan-Meier method and prognostic factors by log-rank test and Cox model. Results: The study included 151 patients. Median age was 60 (range, 14-81). Primary tumor was pancreatic in 86 patients (56.95%) and intestinal in 65 patients (43.05%). Tumors were metastatic (synchronous or metachronous) in 72 patients (47.7%). The median OS was 157 months. For all IP-NETs, age >65 years (P<0.0001), Ki67 >5% (P=0.03), synchronous metastases (P=0.016), primary tumor size >25 mm (P=0.03) and emergency surgery (P=0.007) were independent poor prognostic factors. Conclusions: In this large series of patients with IP-NET, age >65 years, Ki67 >5%, primary tumor size >25 mm, synchronous metastases and emergency surgery for acute complications have been identified as independent poor prognostic factors.