Endocrine carcinoma of the stomach: clinicopathological analysis of 27 surgically treated cases in a single institute

Gastric endocrine carcinoma (EC) is an uncommon tumor of the stomach and the clinical features are not well known. Additionally, the classification and staging systems of this tumor are not yet unified worldwide. In this study, we reviewed 27 patients with gastric EC to evaluate the clinicopathological characteristics of this tumor. We retrospectively reviewed 27 patients with gastric EC among 6466 patients who had undergone gastrectomy between 1986 and 2008 at our institute. Clinicopathological features including immunohistochemistry of Ki-67 were investigated to evaluate the malignant potential of the tumor. Furthermore, survivals were compared between the 7th edition of the International Union Against Cancer (UICC)-TNM (7th TNM) classification for gastric cancer (GC) and the new TNM classification for foregut neuroendocrine tumors (NET). The median survival of the patients was 19.0 months. The 5-year survival rate was 100% in pathological stage (pStage) I, 40% in pStage II, 38% in pStage III, and 11% in pStage IV according to the 7th TNM classification for GC. Survivals by stage showed great difference between the 7th TNM classification for GC and the new TNM classification for foregut NET, but each system correlated with survival. The Ki-67 labeling index was more than 20% in most of the patients. Univariate analysis revealed that maximum tumor diameter, tumor depth, lymph node metastasis, lymphatic invasion, pStage, and curability had significant correlations with survival. Early detection and curative operations are essential for improving the prognosis of gastric EC. However, some adjuvant chemotherapies are required for advanced-stage tumors. Classification and staging systems may need to be unified worldwide for further analysis.