Perineural Invasion of Pancreatic Ductal Adenocarcinoma is Associated with Early Recurrence after Neoadjuvant Therapy Followed by Resection.

BACKGROUND: Neoadjuvant therapy (NAT) is increasingly utilized in the treatment of pancreatic ductal adenocarcinoma (PDAC). However, there are limited data on risk factors and patterns of recurrence after surgical resection. This study aimed to analyze timing and recurrence patterns of PDAC after NAT followed by curative resection. METHODS: The medical charts of patients with PDAC treated with NAT followed by curative-intent surgical resection at a single health system from January 1, 2012 to January 1, 2020 were retrospectively reviewed. Early recurrence was defined as recurrence within 12 months of surgical resection. RESULTS: 91 patients were included and median follow up was 20.1 months. Recurrence occurred in 50 (55%) patients, with median recurrence free survival (RFS) of 11.9 months. Overall, 18 (36%) patients had local and 32 (64%) had distant recurrences. Median RFS and overall survival (OS) between local and distant recurrence were similar. Perineural invasion (PNI) and the presence of a T2 + tumor was significantly higher in recurrence group than in no recurrence group. PNI was a significant risk factor for early recurrence. CONCLUSION: After NAT and surgical resection of PDAC, disease recurrence was common, with distant metastasis being the most common. PNI was significantly higher in the recurrence group.