Pathological and Radiological Splenic Vein Involvement are Predictors of Poor Prognosis and Early Liver Metastasis After Surgery in Patients with Pancreatic Adenocarcinoma of the Body and Tail

Background: The prognostic impact of pancreatic ductal adenocarcinoma (PDAC) invasion to the splenic vessel is controversial. Objective: The aim of this study was to assess the clinical value of pathological and radiological splenic vessel invasion in PDACs of the body and tail. Methods: Medical records of patients with resectable PDAC of the body and tail who underwent distal pancreatectomy between 2003 and 2016 at the Kobe University Hospital were retrospectively analyzed. Results: Overall, 68 patients (29 female and 39 male patients) were enrolled. Pathologically determined splenic vein invasion (p-SV) and splenic artery invasion (p-SA) were identified in 21 (30.9%) and 5 (7.4%) patients, respectively. The p-SV (but not p-SA) was an independent prognostic factor in multivariate analysis (p = 0.009). On analysis of recurrence patterns, patients with PDAC positive for p-SV were at a higher risk for liver metastasis (p = 0.022); however, the associations were not significant for other recurrence patterns. Liver metastasis occurred earlier in patients who were positive for p-SV (p = 0.015). Preoperative computed tomography effectively diagnosed pathological vessel invasion (SV: sensitivity, 95.2%, specificity, 72.3%; SA: sensitivity, 100%, specificity, 84.1%). Radiological SV invasion remained significant in multivariate analysis regarding postoperative survival (p = 0.007), and was also associated with early liver metastases (p = 0.008). Conclusions: Pathological/radiological SV invasion were independent adverse prognostic factors associated with early liver metastasis in patients with PDAC of the body/tail. Assessment of these findings may be useful in determining optimal therapeutic options in these patients.