Endoscopic treatment of unresectable perihilar cholangiocarcinoma: beyond biliary drainage.

Perihilar cholangiocarcinoma (PHCC) is an aggressive biliary malignancy originating from the epithelial cells of the bile duct, typically located in the extrahepatic biliary tree, proximal to the cystic duct. PHCC often presents with a rapid onset of jaundice. While radical surgical resection remains the only curative treatment, only a minority of patients are eligible due to early metastasis and challenges associated with preoperative evaluations. Comprehensive treatments, including chemotherapy, radiotherapy, targeted therapy, and immunotherapy, are crucial for managing PHCC. However, in advanced stages, complications such as cholestatic liver injury, malnutrition, and biliary infections pose significant obstacles to these treatments. Therefore, biliary drainage (BD) is essential in the management of PHCC. In addition to external drainage methods like percutaneous transhepatic biliary drainage (PTBD), endoscopic biliary drainage (EBD), particularly endoscopic retrograde cholangiopancreatography (ERCP), offer an effective option for internal drainage, which is more physiologically compatible and better tolerated. Furthermore, the integration of various endoscopic techniques has expanded the management of PHCC beyond mere drainage. Techniques such as radiofrequency ablation (RFA), photodynamic therapy (PDT), and endoscopic ultrasound (EUS) based methods present new therapeutic avenues, albeit with variable results. This review aims to summarize current advancements and ongoing debates in the field of endoscopic treatment for unresectable PHCC.