Endocrine Abstracts

Introduction: Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors arising from neuroendocrine cells in the endocrine and central nervous system, the natural history of which remains inadequately understood. Large epidemiological studies are gradually emerging from different countries worldwide, which contribute to the establishment of a spherical view about these tumors. The purpose of this study is to evaluate the epidemiological, clinical and pathological characteristics of patients with NENs that have visited the specialized, multipotent medical center of a University Hospital in Athens, Greece.

Methods: 311 patients with NENs were recruited at the specialized, outpatient Medical Center of Neuroendocrine Tumors of the Endocrine Department of ‘Sotiria’ University Hospital in Athens, Greece, during the period from September 2013 till the end of 2014. Anthropometric, clinical, laboratory, imaging and pathologic data were obtained from every patient.

Results: 55.9% of patients with NENs were female and 44.1% were male. The mean age at the time of diagnosis was 52.77±16.7 years old. The majority of NENs were detected in the gastroenteropancreatic system. The most common primary site was stomach (23.8%), followed by pancreas (19.6%) and appendix (12.9%). In 31 patients (10%) the primary tumor remained unknown. Over half of NENs were regional at the time of diagnosis, 18.6% of patients had locally extended disease, while 25.4% of NENs, involving mostly NENs of unknown origin, pancreas and small intestine, were metastatic. Simultaneously, most of them displayed a Ki-67 index of ≤2%, while G3 classification, with a high proliferation index was only observed in pancreatic, rectal and rare NENs. Laboratory data revealed that CgA can predict whether a NEN is metastatic or not, but cannot predict how aggressive its behavior can be. On the contrary, NSE cannot be used as prognostic marker both in disease extent and grading of NENs. Finally, it was observed that patients with CgA levels in the highest quartile (CgA>237 ng/ml) displayed 8 times higher risk for being metastatic at the time of diagnosis (OR=8.643, 95% CI=2.576–9.0).

Conclusions: This is one of the first large, epidemiological studies in Greece, evaluating the natural course of NENs through the experience of a specialized medical center. NENs of the gastroenteropancreatic system were most common, mainly regional at the time of diagnosis and with a Ki-67 index of ≤ 2%. CgA can be a useful marker in predicting disease extent of NENs.