What we have learnt from the past – would treament decicions for GEP- NET patients differ between 2012 to 2016 by the new recommendations in 2022?

Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of tumors with a broad range of local and systemic treatment options. Still a lack of data regarding treatment sequences exists. The aim of this study was to analyze outcomes in GEP-NETs depending on stage and treatment steps and compare our treatment decisions to the latest treatment recommendations of ESMO 2020 for GEP-NETs. Methods: Patients were included in this retrospective single-center analysis from 2012 - 2016. Patient outcomes and treatment lines were analyzed by uni- and multivariable analysis. Results: Overall, we identified 256 GEP-NETs , mostly staged at advaced stage (62%) and located in small intestine tract and pancreatic gland. Survial depended on stage, grade, primary site and duration of response for the early systemic treatment. On average patients underwent 2.6 different treatment modalities, mostly depending on stage and higher tumor grade. Surgery was performed either early but as well in advanced stages, ususally followed by Somatostatine-Antagonist modalities. According to these findings, we formed a suggested treatment algorithm for advanced GEP-NETs, which does not differ from the latest treatment recommendation by ESMO guidelines for GEP-NETs. Conclusion: The results of this project may define GEP-NET patients’ selection for upcoming clinical prosepctive studies.