Outcome after pancreatectomy for neuroendocrine neoplams according to the WHO 2017 grading system: A retrospective multicentric analysis of 138 consecutive patients

Aim: The aim of this study was to evaluate the new World Health Organization (WHO) 2017 grading system and the others clinicopathological factors in pancreatic neuroendocrine tumor (panNET) operated patients. Methods: Histological staging was based on the WHO 2017 grading system. Outcome after surgery and predictors of overall survival (OS) and disease free survival (DFS) were evaluated. Results: A total of 138 patients underwent surgical resection with a severe morbidity and mortality rates of 14.5% and 0.7% respectively. Five years OS differed according to WHO 2017: 95% among 58 patients with NETG1, 82% in 68 patients with NETG2, 35% in 7 patients with NETG3 and 0% in 5 patients with NECG3 (P < 0.0001). Independent predictors of worse OS were age > 60 y.o (P = 0.014), synchronous metastasis (P = 0.005) and WHO 2017 with significant differences between NETG1 versus NETG2 (P = 0.005), NETG3 (P < 0.001) and NECG3 (P < 0.001). Independent predictors of worse DFS were symptomatic NET (P = 0.038), pN+ status (P = 0.027) and WHO 2017 with significant differences between NETG1 versus NETG3 (P = 0.014) and NECG3 (P = 0.009). Conclusion: The WHO 2017 grading system is a useful tool for patient prognosis after panNET resection and the tailoring of therapeutic strategy. Surgery could provide good results in NETG3 patients.