Clinical analysis of gastroenteropancreatic neuroendocrine tumor with liver metastasis, compared with primary hepatic neuroendocrine tumor

Objective: The objective was to study the clinicopathologic features, grading, treatment protocols, and prognostic of gastroenteropancreatic neuroendocrine tumor (NET) with liver metastasis and primary hepatic NET. Materials and Methods: The clinical data of 34 patients with hepatic NET were retrospectively reviewed. According to the primary tumor location and 2010 World Health Organization classification, the cases were categorized to analyze the clinicopathologic features, treatment condition, and prognostic factors. Results: There was a marked male predominance either in gastroenteropancreatic NET liver metastasis group or primary group. Primary hepatic NET is mostly single nodule located in the right lobe of liver, and the metastatic hepatic NET is mostly from pancreas with multiple nodules and metastasizes to both lobes of the liver, with a high degree of malignancy and poor prognosis. There are 17 cases (50%) of NET and 17 cases (50%) of neuroendocrine carcinoma (NEC) in all the 34 patients of this study. The mitotic figure and Ki-67 proliferation index are both higher in NEC group than in NET group, which indicated highly malignancy of the NEC. The 5-year disease-free survival (DFS) rates for primary group and metastatic group were 30% and 40%, respectively (P > 0.05), while the 5-year survival rates were 35% and 66%, respectively (P > 0.05). Different tumor grade was found closely associated with 5-year DFS (P < 0.05) and overall survival (OS) (P < 0.05) in both groups. Furthermore, we found 5-year DFS of patients with primary site of the tumor located in the gastrointestinal tract was much lower than that located in pancreas (P < 0.05), while the 5-year OS showed no significant differences between two groups (P > 0.05). Conclusions: Surgery is an effective method for the treatment of hepatic NET; tumor grading is an important determinant factor of prognosis.