The aim of this study is to investigate the clinicopathological characteristics, as well as explore the prognostic accuracy of the proposed new classification in gastrointestinal NENs (GI-NENs) patients.Patients diagnosed with GI-NENs were retrospectively indentified from existing databases of the pathological institute at our institution from January 2009 to November 2015.We identified 414 patients with GI-NENs, 250 cases were diagnosed as neuroendocrine tumor G1 (NET G1), 25 as neuroendocrine tumor G2 (NET G2), 53 as neuroendocrine tumor G3 (NET G3), 55 as neuroendocrine carcinoma G3 (NEC G3), and 31 as mixed adenoneuroendocrine carcinoma (MANEC); the overall survival (OS) rate at three years were 94.9%, 91.7%, 74.3%, 62.7% and 38.1%, respectively. The difference in progression-free survival (PFS) duration among the patients with NET G1, NET G2, NET G3, NEC G3, and MANEC was statistically significant (P 0.001). However, the PFS of NEC G3 and MANEC was low and similar (P = 0.090). In multivariate analysis of patients with GI-NENs, surgical margin, comorbidity, proposed new classification and tumor location were useful predictors of OS (P 0.05).Our findings suggest that the proposed new classification can accurately reflect the clinical outcome, together with surgical margin, comorbidity, and tumor location may be meaningful prognostic factors for the OS of GI-NENs.
