The Role of Resolvin D1 in the Differential Diagnosis of the Cholangiocarcinoma and Benign Biliary Diseases.

Background: The discrimination of malignant biliary strictures from benign biliary diseases (BBDs) is challenging and complicated. We aimed to investigate whether Resolvin D1 (RvD1) would aid in the discrimination of cholan-giocarcinoma (CCA) from BBDs.

Methods: Thirty-one patients with CCA, 27 patients with BBD, and 30 healthy controls were enrolled in this cross-sectional study. The diagnosis of CCA was based on results obtained from abdominal USG, MRCP, abdominal CT, endosonography, and tumor markers, including CEA and CA 19-9. Histopathological evaluation was performed in the majority of patients, and the final diagnosis was based on surgery or biopsy results. RvD1, CEA, and CA 19-9 were analyzed in all patients with CCA and BBD.

Results: RvD1 was significantly lower in those with CCA compared to patients with BBD and healthy controls. In addition, CEA and Ca 19-9 levels were significantly higher in the CCA group than the BBD group (p < 0.001). RvD1 concentration, CA 19-9 concentration, and total bilirubin level were found to be correlated with tumor stage (r = -0.702, 0.390, and 0.569, respectively). ROC curve analysis revealed that an RvD1 concentration of < 380 ng/mL (AUC: 0.783, 95% CI: 0673 - 0.893, p < 0.001) and CA 19-9 concentration of > 94.5 U/mL (AUC: 0.94, 95% CI: 0.898 - 0.998, p < 0.001) could be used to discriminate patients with CCA from those with BBD.

Conclusions: Resolvin D1 and CA 19-9 levels might be used to effectively discriminate between BBD and CCA. Moreover, both RvD1 and CA 19-9 levels are associated with the stage of CCA, indicating that they may also be used in assessing disease progression.