Objective: Neuroendocrine tumors are rare but constitute a heterogeneous group of tumors in terms of localization and clinical prognosis. The aim of this study was to determine the demographic charecteristics of patients with neuroendocrine tumors and prognostic factors in the clinical course of the disease in a single reference center.

Material and Method: Patients with a diagnosis of neuroendocrine tumors referred to Istanbul University Cerrahpasa Medical Faculty Medical Oncology department between January 1994 and September 2015 were included in the study. The files of 110 patients were retrospectively analysed.

Results: The mean age of the patients was 55±13 years and 57% were male. The most common site of origin was pancreas (30%). Seventy percent (n =77) of patients were metastatic at diagnosis and liver was the most frequent site of metastasis. While the most common symptom firstly reported by the patients was abdominal pain (51%), the rate of asymptomatic cases was 12%. When metastatic disease and tumor markers were compared, there was a significant difference among carcinoembryonic antigen levels (p =0.02). The degree of differentiation associated with neuron specific enolase levels (p =0.008). Mortality was associated with older age (p <0.001), poor differentiation (p <0.001) and presence of metastasis at diagnosis (p =0.002). In patients whose tumor markers were evaluated, high neuron specific enolase levels were associated with mortality (p =0.005).

Conclusion: In our study; older age, poor diferantiation and presence of metastases at initial presentation were found to have an effect on mortality. Early diagnosis and multidisciplinary approach can provide better results in treatment of these patients.