Modification of AJCC TNM staging for intrahepatic cholangiocarcinoma with hepatolithiasis: a multi-institutional retrospective study

Abstract Background Intrahepatic cholangiocarcinoma (ICC) with stones has a worse long-term prognosis than without stones. The stone factor is not considered in the American Joint Committee on Cancer (AJCC) TNM staging system 8th edition. This research aimed to determine whether the presence of stones was associated with T, N, and M staging and to develop a revised staging approach for a more precise staging of ICC patients who also presented with stones. Methods 625 ICC patients who had radical resection at three tertiary institutions in Fujian Province, China, between 2012 and 2022 were retrospectively evaluated, and were divided into stone (n = 270) and non-stone groups (n = 355) based on whether combined with hepatolithiasis. In the stone group, overall survival (OS) data was used to develop a modified AJCC staging system called the hepatolithiasis TNM staging system (hlTNM). Both hlTNM and 8th edition AJCC staging were evaluated for their prognostic value in stone group through three-items multivariate analyses and estimated area under ROC curve (AUC). Results Postoperative survival was worse in stone group at the same TNM stage. Three-items multivariate analyses illustrated that hlTNM staging was more appropriate for prognostic assessment. In stone group, hlTNM staging system (AUC = 0.892) outperformed the AJCC staging system (AUC = 0.872) in predicting the 3-year OS. hlTNM staging method regularly outperformed the AJCC staging approach regarding time-dependent ROC curves, demonstrating more precise prognostic stratification. Conclusion hlTNM staging is more effective in directing physicians’ management of ICC patients with stones and increases the accuracy of OS prediction.