Survivals of patients with pancreatic neuroendocrine carcinomas: An in-depth analysis by the American Joint Committee on Cancer 8th tumor-node-metastasis staging manual

Recently, the American Joint Committee on Cancer (AJCC) 8th staging manual stipulated the World Health Organization (WHO) G3 pancreatic neuroendocrine carcinomas (p-NECs) should all be classified by the system for pancreatic exocrine adenocarcinomas, which had ignored the heterogeneity of G3 p-NECs. We focused on demonstrating whether the heterogeneous subgroups of G3 p-NECs would influence the accurate application of AJCC 8th staging systems.G3 p-NECs were divided into well-differentiated and poorly-differentiated subgroups, whose clinical features and overall survival (OS) were compared. Survival analysis by applying 2 new AJCC 8th staging systems to well-differentiated G3 p-NECs were performed to validate whether these subgroup patients should also be staged by the system proposed for all G3 p-NECs.We enrolled 172 patients who were histopathologically diagnosed as G3 p-NECs, including 64 well-differentiated G3 p-NECs and 108 poorly-differentiated ones, whose patient demographics and tumor characteristics present no notably differences (P > .05), except their Ki-67 index and mitotic rate (P = .031, P = .025; respectively). The estimated OS of well-differentiated G3 p-NECs was significantly better than those of poorly-differentiated tumors (P