An Externally Validated Risk Score for Intrahepatic Cholangiocarcinoma Following Surgical Resection: A SEER Database Analysis

Background: Surgery in the form of hepatectomy remains the only curvative option for patients with intrahepatic cholangiocarcinoma (iCCA). However the long-term survival for iCCA patients following hepatectomy remains poor. We sought to develop a post-operative score to predict the patient survival following liver resection for iCCA and validate the score on a local population. Methods: The Surveillance, Epidemiology, and End Results (SEER) database identified patients with histologically confirmed iCCA between 1998 - 2013 as the derivation cohort. Prognostic factors were evaluated using Kaplan-Meier curves and Cox proportional hazards models. Primary end-points assessed in the study was overall Survival (OS). The score was externally validated upon a patient cohort from the United Kingdom. Results: The derivation cohort included 809 patients undergoing surgical resection for iCCA. Multivariate Cox regression model identified male (p=0.013), multifocal tumours (p<0.001), local invasion (p=0.027), vascular invasion (p=0.002), poor/anaplastic differentiation (p< 0.001), tumour size >5cm (p=0.013) and N classification (p<0.001) as prognostic factors. The corresponding c-statistic for the derived score was 0.71 (CI95: 0.67 - 0.76) for the derivation cohort and 0.80 (CI95%: 0.65 - 0.92) for the validation cohort (p=0.001). Conclusion: This novel risk score derived from a large national database, with external validation, may be useful in guiding post-operative management of patients following surgical resection for iCCA.