Surgical Challenges Associated with Collateral Veins Formation in Pancreatic Cancer with Vein Resection.

[BACKGROUND] Advanced pancreatic ductal adenocarcinoma (PDAC) often infiltrates or obstructs the superior mesenteric vein (SMV)/portal vein, leading to collateral vein (CV) formation. Although CVs are hypothesized to affect surgical outcomes, data regarding their clinical significance remain limited. This study aimed to evaluate the impact of CV formation on short-term outcomes in patients with PDAC who underwent portomesenteric venous resection (PVR).

[METHODS] We retrospectively analyzed PDAC cases undergoing PVR at our institution between 2010 and 2023. CVs were identified using preoperative computed tomography, and patients were categorized based on the presence or absence of CVs. Short-term outcomes were assessed prospectively. A subgroup analysis was performed to evaluate the clinical relevance of proximal versus distal SMV involvement.

[RESULTS] Among 403 patients with PDAC undergoing PVR, 27 (6.7%) had CVs. The CV group exhibited significantly longer operative times (median: 618 vs. 517 minutes, p < 0.0001) and greater blood loss (median: 1500 vs. 590 mL, p < 0.0001). Postoperative complications (Clavien-Dindo classification ≥IIIa) were more frequent in the CV group (33.3% vs. 10.1%, p = 0.002). Multivariate analysis identified CV formation as the strongest predictor of blood loss ≥1000 mL (odds ratio: 6.63 [95% confidence interval 2.70-17.3], p < 0.0001). As expected, distal SMV involvement correlated with longer operative times but did not impact other outcomes.

[CONCLUSIONS] CV formation, a characteristic feature of advanced PDAC, was strongly associated with increased surgical difficulty and postoperative complications, highlighting the need for tailored strategies to optimize outcomes in PDAC cases undergoing PVR.