Proposal of a modified classification for hilar cholangiocarcinoma

Hilar cholangiocarcinoma is a malignant tumor that originates from the left and right hepatic ducts and their confluence. It is highly malignant and associated with a poor prognosis. Surgical resection is the only available curative treatment option. A scientific classification system can aid in the preoperative assessment of resectability and guide the development of appropriate surgical strategies. Several classification systems are available, with the Bismuth-Corlette (BC) classification being the earliest and most widely used. Similar to many other classifications, the BC classification relies on the secondary branching of the bile ducts as an important anatomical landmark, making it unsuitable for cases with variations in the bile duct anatomy. With advances in understanding the hepatic plate and anatomical structures at the hilum, the secondary bile ducts are no longer considered important anatomical landmarks. Therefore, modifications to the BC classification are needed to align with modern anatomical improvements and advancements in surgical techniques. Herein, we propose a modification to the BC classification. In this new system, the boundary of the hilar plate is considered as limit of the proximal ductal margin and used as an anatomical landmark, rather than the concept of “secondary bile ducts” in the BC classification.