Local Recurrence and Survival Outcomes after Portal Vein/Superior Mesenteric Vein Separation without Resection Preceding Neoadjuvant Therapy for Pancreatic Ductal Adenocarcinoma.

In patients with pancreatic ductal adenocarcinoma (PDAC) and portal vein/superior mesenteric vein (PV/SMV) contact, we can often separate the tumor from the PV/SMV and avoid PV/SMV resection (VR) owing to the favorable efficacy of neoadjuvant therapy (NAT). However, there is a risk that tumor cells may remain around the PV/SMV. This study aimed to elucidate whether separating a tumor from a PV/SMV is justified in the NAT setting. Methods: We reviewed patients with PDAC who underwent pancreaticoduodenectomies or total pancreatectomies between 2005 and 2019. We usually attempt the skeletonization of PV/SMV as long as possible. We explored recurrence patterns and overall survival (OS). Results: In total, 248 patients were enrolled and divided based on PV/SMV contact (PVC), NAT, and VR. In the NAT setting, local recurrence around PV the SMV occurred at almost the same rate among the three groups (8.1%, NAT+/PVC-; 11.8%, NAT+/PVC+/VR-; 13.6%, NAT+/PVC+/VR+), while the NAT-/PVC+/VR- had a higher local recurrence rate in upfront surgery (10.0%, NAT-/PVC-; 33.3%, NAT-/PVC+/VR-; 12.2%, NAT-/PVC+/VR+, P=0.021). In addition, the OS in the NAT+/PVC+/VR- was not inferior to that in the NAT+/PVC- (Median survival time: 46.6 months, NAT+/PVC-; 61.1, NAT+/PVC+/VR-; 33.0, NAT+/PVC+/VR+). Conclusions: Separation of the PV/SMV in NAT+/PVC+ patients did not enhance local recurrence or aggravate OS if PV/SMV invasion was not suspected intraoperatively. Therefore, an attempt to separate the PV/SMV is acceptable.