Highlights of topic "Pancreatic neuroendocrine tumors update".

Abstract

Pancreatic neuroendocrine tumors (PNETs) are becoming an increasing clinical problem because the number of patients has been increasing and PNETs can frequently present with advanced disease that requires distinct diagnostic and treatment approaches in Japan. There have been a number of advances in all aspects of PNETs including: an understanding of their unique pathogenesis; development of specific classification systems, which have prognostic value; development of novel methods of tumor localization; and description of novel treatment approaches. In patients with advanced metastatic disease these include the use of newer chemotherapeutic approaches, an increased understanding of the role of surgery and the new concept of cytoreductive methods, the development of methods for targeted delivery of cytotoxic agents and the development of molecular targeted medical therapies, such as everolimus and sunitinib, based on an increased comprehension of their biology. In this issue, we highlight the update of PNETs over the last few years. First, the World Health Organization (WHO) classification was revised in 2010 and the current WHO classification categorizes PNETs into three categories based on the mitotic index and Ki67-labeling index (Kasajima et al. 1, Table 1). This classification also greatly contributes to predicting clinical outcomes of patients with PNETs and subsequently determines their therapeutic strategies. Next, regarding the epidemiology for PNETs, the second nationwide survey in Japan was conducted on patients with PNETs who received treatment in 2010. The epidemiological changes in these patients from 2005 to 2010 were clarified. Furthermore, the clinical guidelines for gastroenteropancreatic neuroendocrine tumors in Japan were published by the Japan Neuroendocrine Tumor Society (JNETS) in 2013. The JNETS guidelines describe in detail the strategies for diagnosis for PNETs, determinants of resection for PNETs and the management and treatment of patients with advanced metastatic PNETs. Until now the mode of resection for non-functioning PNETs has been unclear; however, in the JNETS guidelines atypical resections have been proposed in the management of non-functioning PNETs, especially when well demarcated and small in size (Doi 2, Fig. 4). Furthermore, this issue provides the most updated information on chemotherapy with a focus on poorly differentiated NEC (NEC G3). Recently, well-differentiated NET G3 with a Ki-67 index of ≥20%, which is included in NEC by the WHO classification, has become a topic of conversation. Finally, a number of different somatostatin analogs and attached chelators have been used in various studies to allow binding of the radioisotope, with the most frequent chelator being DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra-acetic acid). In the very near future 68Ga-DOTATOC・PET/CT, which might become useful to visualize most small gastrinoma less than 5 mm (Imamura et al. 3, Fig. 5), can be used in Japan. We hope this issue of the journal contributes to greater understanding of the available diagnostic and treatment approaches for PNETs. None declared.