LAUSR

BACKGROUND Neuroendocrine neoplasms (NENs) are rare tumours with variable clinical behaviour. Their natural history is ideally best approached in large, multicentre and multinational registries with long-term patients' follow-up. The European Neuroendocrine Tumour Society registry aims to obtain information regarding NEN outcomes and prognostic factors in a European frame. PATIENTS AND METHODS We collected data from 7 national NEN registries (Belgium, Czech Republic, Germany, Greece, Poland, Spain, Switzerland), representing 10,102 patients. Anonymised/pseudonymised data were collected in a secured server. Descriptive statistical methods were applied, as well as Kaplan-Meier survival curves and multivariable analyses for prognostic factors of overall survival (OS). RESULTS median age of the study population was 60 years (range: 18-102), 48% were female. Common primary tumour sites were pancreas (27%) and small intestine (21%). Stage 4 disease was found in 47% of patients, while 26/10/16% had stage 1/2/3 disease, respectively. Grading (n = 6952) was G1/2/3 in 48/37/15% of the patients, respectively. Surgery was the main treatment, provided to 71% of patients, followed by somatostatin analogues (32%), chemotherapy (20%), Peptide receptor Radionuclide Therapy (PRRT) (9%) and targeted therapies (8%). OS at 5 years was 74%, influenced by grade, stage and tissue of origin in multivariate analysis. A Ki67 cut-off value set at 55% within the G3 group allowed to separate 2 groups with a meaningful different OS. CONCLUSION We report the first analysis of the European Neuroendocrine Tumour Society registry, comprising 10,102 patients with NEN from 7 European countries. This large cohort study describes prognostic factors for the survival of NENs throughout Europe, including primary tumour site, grade, stage and treatment.