Shinnosuke Yonaiyama

Prognosis based on the revised histological classification by the World Health Organization (2010) for pancreatic neuroendocrine tumors

Background/aim: Pancreatic neuroendocrine tumors (PNETs) are a rare subgroup of tumors, for which the factors predictive of survival and prognosis are not well known. Recently, the European Neuroendocrine Tumors Society (ENETS) proposed the TNM staging and the World Health Organization (WHO) revised its histological classification in 2010. This study aimed to evaluate whether the ENETS staging and the revised WHO classification can predict survival after surgical resection of PNETs. Methods: Twenty consecutive curative resections for PNETs were performed at our institute from 1998 to 2012. The prognostic factors based on the revised WHO histological classification (2010) for survival were retrospectively evaluated using the Kaplan–Meier method. Results: The mean patient age was 60.3 10.9 years. Twelve patients (60%) were diagnosed with functioning tumors and 8 (40%) with nonfunctioning tumors. Surgical methods comprised pancreatoduodenectomy (n 1⁄4 3), distal pancreatectomy (n 1⁄4 5), enucleation (n 1⁄4 9), and central pancreatectomy (n 1⁄4 3). Hepatectomy was performed for 2 patients with synchronous liver metastasis. According to the ENETS staging, 14 (70%), 2 (10%), 2 (10%), and 2 (10%) had stage I, II, III, and IV tumors, respectively. According to the revised WHO histological classification (2010), 13 (65%), 5 (25%), 1 (5%), and 1 (5%) patient was diagnosed with neuroendocrine tumor (NET) G1, NET G2, neuroendocrine carcinoma (NEC), and mixed adenoneuroendocrine carcinoma (MANEC), respectively. Univariate analysis revealed that both the ENETS staging and the revised WHO histological classification (2010) significantly predicted survival after surgical resection for PNETs. Conclusions: The ENETS staging and the revised WHO histological classification (2010) may be useful to predict survival in PNETs. However, because PNETs represent a rare tumor subgroup, more time and a sufficient number of cases are required to confirm its prognostic reliability.

Tu1216 Epithelial Cell Adhesion Molecule (EpCAM) Overexpression Is Correlated With Malignant Potentials of Intraductal Papillary Mucinous Neoplasms (IPMNs) of the Pancreas

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas exhibit a wide range of histopathological variation. Epithelial cell adhesion molecule (EpCAM) is a 40 kDa type I membrane protein that is known to be highly expressed in epithelial carcinomas. In this study, we examined immunohistochemical expression of EpCAM in the pancreatic IPMNs in order to clarify its clinicopathological significance. We analyzed 51 cases of surgically resected IPMNs: 32 cases of adenoma; 6 cases of non-invasive carcinoma; 8 cases of minimally invasive carcinoma; and 5 cases of invasive carcinoma. Additionally, these 51 cases were classified into four phenotypes (gastric, intestinal, pancreatobiliary and oncocytic). EpCAM overexpression was found in 16 (31.4%) of the tumor samples. We found five predictive factors of malignancy using the univariate analysis as follows; serum CA19-9 level, main pancreatic duct diameter, presence of mural nodule, phenotype and EpCAM overexpression. In the multivariate analysis, only EpCAM overexpression was identified to be independently associated as a predictive factor for malignancy (odds ratio, 11.039; 95% confidence interval, 1.877-64.919; P-value, 0.008). Our study is the first report to demonstrate that EpCAM overexpression is an independent factor for malignancy; therefore, EpCAM overexpression is thought to be a novel predictor of malignant IPMNs.