Advances in Application of PDT Combined with Multiple Therapies on Unresectable Extrahepatic Cholangiocarcinoma

Cholangiocarcinoma is a malignant tumor originating from the bile duct epithelium, with the increasing incidence year by year. Its early symptoms are atypical and the diagnosis rate is low. Most of the patients are already in advanced stage when they are diagnosed, losing the best surgery period. Currently, the conservative treatments for unresectable extrahepatic cholangiocarcinoma include stent placement, radiofrequency ablation, radiotherapy and chemotherapy, targeted and immunotherapy and other systemic treatments. But due to the high malignancy of biliary tract tumors, the tendency to develop drug resistance and the limited population benefited from the emerging treatment modalities, we urgently need to explore new treatment strategies to break this bottleneck. As a new treatment for cholangiocarcinoma, photodynamic therapy has attracted much attention for its clinical application and therapeutic effects. In this paper, we summarize the principles of photodynamic therapy, the combination of photodynamic and other therapeutic modalities, especially the combination of photodynamic with emerging immune and targeted therapies, and describe the current hotspot directions of photodynamic therapy research at home and abroad to provide reference for clinical treatment and research.