Dear Editor,

I read the recent publication by Sasaki et al. with great interest. Sasaki et al. concluded that “Patients who underwent surgical resection were not evenly divided across UICC-TNM staging categories in comparison to JSBS staging. Stratification of survival ability was better when using the JSBS staging in comparison to the UICC-TNM system [1].” I agree that JSBS might be a good classification system. However, there are still some remaining questions. In general, there are many other systems for the classification of cholangiocarcinoma including the American Joint Committee on Cancer, Bismuth–Corlette, and the modified Memorial Sloan-Kettering Cancer Center classification [2, 3]. Additional comparative assessment of those systems will give useful data on making a decision in using the best classification system. Also, the cost and effectiveness of each system, which might be different due to system-specific criteria, should be focused and further cost-effectiveness analysis should be done.