Performance of prognostic scores and staging systems in predicting long-term survival outcomes after surgery for intrahepatic cholangiocarcinoma

Introduction: We sought to validate the commonly used prognostic models and staging systems for intrahepatic cholangiocarcinoma (ICC) in a large multi-center patient cohort. Methods: The overall (OS) and disease free survival (DFS) prognostic discriminatory ability of various commonly used models were assessed in a large retrospective cohort. Harrell's concordance index (c-index) was used to determine accuracy of model prediction. Results: Among 1054 ICC patients, median OS was 37.7 months and 1-, 3-, and 5-year survival, were 78.8%, 51.5%, and 39.3%, respectively. Recurrence of disease occurred in 454 (43.0%) patients with a median DFS of 29.6 months. One-, 3- and 5- year DFS were 64.6%, 46.5 % and 44.4%, respectively. The prognostic models associated with the best OS prediction were the Wang nomogram (c-index 0.668) and the Nathan staging system (c-index 0.639). No model was proficient in predicting DFS. Only the Wang nomogram exceeded a c-index of 0.6 for DFS (c-index 0.602). The c-index for the AJCC staging system was 0.637 for OS and 0.582 for DFS. Conclusions: While the Wang nomogram had the best discriminatory ability relative to OS and DFS, no ICC staging system or nomogram demonstrated excellent prognostic discrimination. The AJCC staging for ICC performed reasonably, although its overall discrimination was only modest-to-good.