The concentration of D-dimers in portal blood positively correlates with overall survival in patients with non-resectable pancreatic cancer

Background: Several recent studies provide evidence that D-dimer (DD) concentration in peripheral blood correlates negatively with overall survival (OS) in patients with pancreatic ductal adenocarcinoma (PDAC). Contrarily, there are recent evidence indicating that preoperative plasma fibrinogen, but not D-dimer might represent a prognostic factor in non-metastatic gastrointestinal cancers. Methods: In a single-center prospective study, we enrolled 62 patients undergoing surgery for pathologically confirmed PDAC without detectable venous thrombosis. Intraoperatively, the sample of the blood from the portal vein was obtained. DD concentration in these samples was measured. Patients were followed postoperatively until time of death from any cause. Results: We found that OS for patients with portal blood DD values above 2700 (ng/mL) (n = 22 from 62 patients) was higher by 158% than that for the patients (n = 42) with DD values <= 2700 (416 days versus 161 days, p = 0.05). On the contrary to the studies investigating DD concentration in peripheral blood, we have found that patients with higher DD level in the portal vein had longer mean OS than patients with lower ones. Conclusions: Further investigation is necessary both to confirm our results in a larger patient population and to elucidate the mechanism for the correlation between portal blood D-dimer concentrations and survival time. Along with other authors, we conclude that portal circulation is characterized by unique, biological environment that requires further evaluation.