The influence of neural invasion on survival and tumor recurrence in pancreatic ductal adenocarcinoma – A systematic review and meta-analysis

•To assess the impact of neural invasion/Pn on overall survival and tumor recurrence.•Pn decreases overall survival in patients with pancreatic ductal adenocarcinoma/PDAC.•Pn is an independent factor for overall survival in PDAC.•Pn is an independent factor for disease- and recurrence-free survival in PDAC.