A comprehensive validation of the novel 8th edition of American Joint Committee on Cancer staging manual for the long-term survivals of patients with non-functional pancreatic neuroendocrine neoplasms

• Published in: Medicine (Baltimore) Vol. 99; no. 46; p. e22291
• Main Authors: Yang, Min, Zeng, Lin, Yao, Wen-Qing, Ke, Neng-Wen, Tan, Chun-Lu, Tian, Bo-le, Liu, Xu-Bao, Xiang, Bo, Zhang, Yi
• Format: Journal Article
• Language: English
• Published: United States Lippincott Williams & Wilkins 13.11.2020
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Female; Humans; Kaplan-Meier Estimate; Male; Medical Oncology - instrumentation; Medical Oncology - methods; Medical Oncology - organization & administration; Middle Aged; Neoplasm Staging - methods; Neuroendocrine Cells - pathology; Observational Study; Pancreatic Neoplasms - classification; Pancreatic Neoplasms - diagnosis; Retrospective Studies; Textbooks as Topic - standards; United States; United States
• ISSN: 0025-7974; 1536-5964
• DOI: 10.1097/MD.0000000000022291

Histologically, the World Health Organization has classified pancreatic neuroendocrine neoplasms (p-NENs) into well-differentiated pancreatic neuroendocrine tumors (G1/G2 p-NETs) and poorly-differentiated pancreatic neuroendocrine carcinoma (G3 p-NECs) based on tumor mitotic counts and Ki-67 index. Recently, the 8th edition of American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging manual has incorporated some major changes in 2017 that the TNM staging system for p-NENs should only be applied to well-differentiated G1/G2 p-NETs, while poorly-differentiated G3 p-NECs be classified according to the new system for pancreatic exocrine adenocarcinomas. However, this new manual for p-NENs has seldom been evaluated.Data of patients with both G1/G2 and G3 non-functional p-NENs (NF-p-NENs) from our institution was retrospectively collected and analyzed using 2 new AJCC 8th staging systems. We also made survival comparisons between the 8th and 7th edition system separately for different subgroups.For G1/G2 NF-p-NETs, there were 52 patients classified in AJCC 8th edition stage I, 40 in stage II, 41 in stage III and 19 in stage IV. As for G3 NF-p-NECs, 17, 19, 24, and 18 patients were respectively defined from AJCC 8th edition stage I to stage IV. In terms of the AJCC 7th staging system, the 230 patients with NF-p-NENs were totally distributed from stage I to stage IV (94, 63, 36, 37, respectively). For the survival analysis of both G1/G2 NF-p-NETs and G3 NF-p-NECs, the AJCC 7th edition system failed to discriminate the survival differences when compared stage III with stage II or stage IV (P > .05), while the 8th edition ones could perfectly allocate patients into 4 statistically different groups (P < .05). The HCIs of AJCC 8th stage for G1/G2 NF-p-NETs [HCI=0.658, 95% confidence interval (CI)=0.602-0.741] and stage for G3 NF-p-NECs (HCI=0.704, 95% CI=0.595-0.813) was both statistically larger than those of AJCC 7th stage for different grading NF-p-NENs [(HCI=0.578, 95% CI=0.557-0.649; P=.031), (HCI=0.546, 95% CI=0.531-0.636; P = .019); respectively], indicating a more accurate predictive ability for the survivals of NF-p-NENs.Our data suggested the 2 new AJCC 8th staging systems were superior to its 7th edition for patients with both G1/G2 NF-p-NETs and G3 NF-p-NECs.