Original Article Well differentiated neuroendocrine tumors, a single center experience Ece Esin * , Berna Oksuzoglu, Erkan Erdur, Guliz Ozgun, Umut Demirci University of Health Sciences, Dr. A.Y Ankara Oncology Education and Research Hospital, Department of Medical Oncology, Demetevler, Ankara, Turkey article info Article history: Received 12 August 2018 Received in revised form 27 October 2018 Accepted 27 October 2018 Available online 8 November 2018 Keywords: Neuroendocrine tumor Grade Ki67 Carcinoid tumor abstract Purpose: The aim of this study is to analyze the demographic, histopathologic features of Neuroendo- crine tumor (NET) cases and to underline the treatment approaches over seven years period in a high- volume cancer center. Methods: This study designed as a retrospective evaluation of NET registry data from a single medical oncology clinic between January 2012 and November 2017. Results: A total of 72 patients'? data were registered. The median age was 54 (18e84) years. The three most common sites of diagnosis were pancreas (19 cases, 26.4%), unknown primary with liver metastasis (15 cases-20.8%) and lung (10e13.9%). There was no association between the extent of disease and grade of NET (p ¼ 0.73). Apart from pancreatic NETs, there was no difference in the stages of disease presen- tation (p > 0.05). Globally, estimated 5-year overall survival (OS) ratewas 77.5% and 10-year OS rate was 57.8%. There was no statistically significant difference in estimated 5- year OS rates of comparison be- tween grade 1 and grade 2 NET's (69.9 vs. 91.8%, p ¼ 0.19). In addition, Ki67 proliferative index did not make any difference in estimated 5- year OS rates (78.1 vs 77.7%, p ¼ 0.71). Conclusions: The multimodality treatment, site specific approaches and radionuclide therapies lead to better response rates and a longer survival in patients. Although there is a difference in distribution and presentation of NET cases compared to previous publications, optimal treatment yields a good Results?. Wherever possible, treatment of NETs is optimally scheduled by a multidisciplinary team, data collection should be centralized and audited by the team to make a clear conclusion for a less acknowledged tumor type. © 2018 Turkish Society of Medical Oncology. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction Neuroendocrine tumors (NET's) are relatively rare tumors, the annual incidence in the United states in 6.98/100000 population which is reported to be increasing. 1,2 The annual prevalence of gastroenteropancreatic NETs (GEP-NET) as a second common ma- lignancy of digestive system, is more than the sum of prevalence of gastric and pancreatic carcinomas. 3,4 NETs are epithelial neoplasms which can originate from any neuroendocrine cell throughout the body, therefore some of clinical and pathological features are shared while others are particular for the site of origin. Various classifications were suggested to group these tumors; lastly World Health Organization (WHO) have published 2010 NET classification which includes the consensus report. According to WHO, Gastroenteropancreatic (GEP) NET are classified as NET grade 1 (G1), NET grade 2 (G2) and neuroendocrine carcinoma (NEC) grade 3 (G3). The grading and proliferation index has prognostic importance. Additionally; site of origin, stage of disease and site of metastasis have prognostic impact on survival of patients. During the last few years, there have been important advances in the diagnosis and management of NET as several treatment op- tions have been made available even for patients with advanced disease, including targeted agents, radionuclide therapies. The aim of this study is to analyze the demographic, histo- pathologic features of NET cases over seven years period in a high- volume cancer center. 2. Methods This study designed as a retrospective evaluation of NET registry data from a single medical oncology clinic. Between January 2012 and November 2017, all of the patients who were carrying tumors in neuroendocrine histology with well differentiated * Corresponding author. E-mail address: dr.eceesin@gmail.com (E. Esin). Peer review under responsibility of Turkish Society of Medical Oncology. Contents lists available at ScienceDirect Journal of Oncological Sciences journal homepage: https://www.elsevier.com/locate/jons https://doi.org/10.1016/j.jons.2018.10.002 2452-3364/© 2018 Turkish Society of Medical Oncology. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). Journal of Oncological Sciences 4 (2018) 119e124