The severity of neural invasion decreases overall survival and time until tumor recurrence in patients with pancreatic ductal adenocarcinoma

Abstract

Introduction: Neural invasion/Pn is recognized as an unfavorable factor decreasing overall survival/OS in patients with pancreatic ductal adenocarcinoma/PDAC. Recently, we could clearly show that Pn is an omnipresent, histopathological feature of PDAC reaching up to nearly 100% of all tumor specimens and that Pn decreases OS and disease-free surviva/DFSl. Yet, the impact of severity of Pn on OS and DFS has not been systematically evaluated. Methods: Therefore, 225 PDAC specimens of patients resected between 07/2007 and 10/2014 were systematically revaluated and our Neural Invasion Severity Score”/NI-SSc was assessed. Afterwards, NI-SSc was correlated with clinical follow-up data focusing on OS and time to tumor recurrence. Results: Overall incidence of Pn was 96%. Strikingly, a high NI-SSc was not even associated with a diminished OS in PDAC patients (median survival: 17.2 months vs. 27.6 months, p = 0.001) but also a strongly decreased DSF (27.7 months vs. 10.5 months, p < 0.001). Moreover, time to local recurrence/LR (10.5 months vs. 27.7 months, p=0.001) and time to distant metastases/DM (12.9 months vs. 27.2 months, p = 0.01) was unfavorably affected by a high NI-SSc in PDAC. Accordingly, NI-SSc was the strongest independent predictor for OS (HR = 1.02; p = 0.01), for LR (HR = 1.05; p < 0.0001) and for DM (HR = 1.01; p = 0.04) by the Multiple Cox proportional hazard model. Conclusion: In PDAC, the severity of Pn is an unfavorable predictor of a crucially shortened OS and time to LR and DM. Therefore, the NI-SSc should gain increased consideration in the planning of individual postoperative treatment for patients with PDAC.