Etoposide/Cisplatin Compared With Irinotecan/Cisplatin for Advanced Gastrointestinal Neuroendocrine Tumor G3 Type

The aim of this study is to investigate the efficacy, safety, and survival benefit of etoposide plus cisplatin and irinotecan plus cisplatin in first-line therapy of non-primary pancreatic metastatic and/or unresectable gastrointestinal neuroendocrine tumor G3 type. In addition, the investigators will explore the resistance mechanisms of gastrointestinal neuroendocrine tumor G3, and screen out biomarkers that can predict the efficacy of chemotherapy.