Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are composed of cells with a neuroendocrine phenotype. The old and the new WHO classifications distinguish between well-differentiated and poorly differentiated neoplasms. All well-differentiated neoplasms, regardless of whether they behave benignly or develop metastases, will be called neuroendocrine tumours (NETs), and graded G1 (Ki67 20%). To stratify the GEP-NETs and GEP-NECs regarding their prognosis, they are now further classified according to TNM-stage systems that were recently proposed by the European Neuroendocrine Tumour Society (ENETS) and the AJCC/UICC. In the light of these criteria the pathology and biology of the various NETs and NECs of the gastrointestinal tract (including the oesophagus) and the pancreas are reviewed.
Gastroenteric neuroendocrine neoplasms (GE-NENs) display highly variable clinical behavior. In an attempt to assess a better prognostic description, in 2010, the World Health Organization (WHO) updated its previous classification, and the European Neuroendocrine Tumors Society (ENETS) proposed a new grading and TNM-based staging system. In the current study, the authors evaluated the prognostic significance of these models and compared their efficacy in describing patients' long-term survival to assess the best prognostic model currently available for clinicians.
The study cohort was composed of 145 patients with extrapancreatic GE-NEN who were observed from 1986 to 2008 at a single center and were classified according to the WHO and ENETS classifications. Survival evaluations were performed using Kaplan-Meyer analyses on 131 patients. Only deaths from neoplasia were considered. A P value