Endobiliary Photodynamic Therapy in Cholangiocarcinoma: Clinical Outcomes, Patient Selection, and Procedural Context.

Endobiliary photodynamic therapy (PDT) in cholangiocarcinoma (CCA) is used mainly for local palliation of malignant biliary obstruction, particularly in extrahepatic and perihilar disease. This Review synthesizes the clinical evidence on endobiliary PDT while using drainage, infection control, stent strategy, light delivery, and systemic-therapy context as an interpretive framework rather than as practice recommendations. This narrative review was informed by targeted searching of PubMed/MEDLINE, Embase, and Web of Science from database inception through to 31 December 2025, supplemented by reference-list screening. We prioritized prospective studies, comparative cohorts, systematic reviews, and relevant guidance documents. Across the literature, the clearest support for PDT concerns selected local biliary palliation, including decompression, stent patency or delayed dysfunction, and symptom relief. Survival signals remain inconsistent: early positive studies contrast with the negative PHOTOSTENT-02 randomized trial and are highly confounded by drainage adequacy, infection control, retreatment strategy, and systemic-therapy access. We therefore interpret PDT as a context-dependent local biliary strategy rather than an established survival-prolonging treatment, and we highlight the clinical variables that make published outcome signals more or less interpretable.