Reply to Dr. Wiwanitkit’s letter to the editor

Excerpt

We are grateful to Dr. Wiwanitkit for his positive review of our recent publication. Dr. Wiwanitkit noted that there are many other systems that can be used to classify cholangiocarcinoma and that additional comparative assessments using these systems will provide useful data that can help us identify the best classification system. We believe that a useful classification contains three categories, including local tumor extension, lymph node metastasis, and distant metastasis in patients with extrahepatic cholangiocarcinoma as well as other gastrointestinal malignancies. The Bismuth–Corlette and modified Memorial Sloan–Kettering Cancer Center classifications [1, 2] both consider local tumor extension, but these two classifications are not commonly used to estimate patient prognosis or evaluate treatment results. The TNM staging of the International Union Against Cancer (UICC) and the classification system of the Japanese Society of Biliary Surgery (JSBS) include these three categories. The JSBS classification was revised five times, and the sixth edition has been revised by reacting to and drawing from the UICC-TNM classification. In order to generate the best classification system, we believe that it is eminently important to compare these two classifications and identify important aspects in these systems. In the near future, these two classifications may become similar and be integrated to generate an improved classification system that will greatly help surgeons assess patients with extrahepatic cholangiocarcinoma. …