Abstract
Introduction: To evaluate the 8th edition of the American Joint Committee on Cancer (AJCC) staging system for perihilar cholangiocarcinoma (PHC), and to compare the prognostic value of the 7th and 8th editions of the AJCC staging system for PHC. Methods: All patients with PHC between 2002-2014 were included. Imaging at the time of presentation was reassessed and AJCC Tumor-Nodal-Metastasis (TNM) stage was determined according to the 7th and 8th edition of the AJCC staging system. Overall survival (OS) was estimated using the Kaplan-Meier method. Comparison of the prognostic accuracy of staging systems was performed using the concordance index (c-index) and Brier-score. Results: A total of 248 PHC patients were included. Median OS of the entire cohort was 9.7 months (8.0-11.5). Prognostic accuracy was comparable between the 7th and 8th AJCC staging systems (c-index 0.59 vs 0.58). Prognostic accuracy of the 8th edition was higher in the subgroup of resected patient (0.67), but expanding the staging system with sub-stages lowered the c-index to 0.62. The prognostic accuracy of the AJCC staging system in unresectable patients was poor with a c-index of 0.57 in both the normal and expanded staging system. Conclusions: The 7 th and 8 th editions of the AJCC staging system for PHC have comparable prognostic accuracy. Although developed to be used for resectable and unresectable patients, the discriminative performance in unresectable patients was poor. Therefore, the AJCC staging system may need modifications to improve its prognostic accuracy in patients with unresectable PHC, compromising the majority of patients.
Highlights
The American Joint Committee on Cancer (AJCC), 8th edition, has revised the T system for distal cholangiocarcinoma (DCC) from layer-based to depthbased approach
This study investigated treatment, outcome and predictors for survival in a nationwide cohort of patients with distal cholangiocarcinoma
Prognostic accuracy of the 8th edition was higher in the subgroup of resected patient (0.67), but expanding the staging system with sub-stages lowered the c-index to 0.62
Summary
Perihilar cholangiocarcinoma (PHC) is a rare tumor that requires multimodal multidisciplinary treatment and is associated with substantial morbidity and mortality. This study aimed to compare a major eastern and western PHC cohort in terms of patient characteristics, treatment strategies and outcomes including a propensity score matched analysis. A propensity score matched analysis based on baseline characteristics to compare perioperative outcomes and a multivariable analysis for survival were performed. After propensity score matching (1:1), the two cohorts both including 79 patients had similar rates of liver failure and morbidity, biliary leakage (33% versus 17%, p=0.03) and morality rates (18% versus 5%) were higher in the west. Discussion: There are major differences in patient characteristics, treatment strategies, perioperative outcomes and survival between eastern and western PHC cohorts. These results indicate that PHC research should not be translated across the world before cross-cardinal external validation.
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