The goal of this clinical trial is to learn about radiofrequency ablation in patients with unresectable bile duct cancer who receive systemic chemotherapy and bile duct stenting. The main questions it aims to answer are:

• Does radiofrequency ablation of tumorous bile duct occlusion reduce risk of complications in these patients (eg stent dysfunction, delay of chemotherapy, infections etc)?
• Is radiofrequency ablation safe in these patients? All participants will receive standard treatment with systemic chemotherapy and bile duct stenting. Researchers will compare two groups (one group will receive additional radiofrequency ablation, the other not).

Inclusion Criteria:

1. Unresectable perihilar and/or ductal CCA with bile duct stenting and palliative systemic therapy as indicated by the local Multidisciplinary Team (MDT)
2. Written informed consent
3. Eastern Cooperative Oncology Group (ECOG) performance status 0-1
4. Age ≥18 years
5. Eligibility for palliative systemic therapy based on clinical and laboratory parameters (except hyperbilirubinemia) as determined by the local MDT
6. No prior radiofrequency ablation (RFA) for CCA
7. No repeated bile duct stenting in the past 3 months (trial inclusion is possible upon first stent replacement or initial stent placement within past 3 months)
8. No concomitant disease or malignancy interfering with the study procedure or efficacy outcome measures, particularly no severe or uncontrolled cardiovascular disease (congestive heart failure NYHA III or IV, unstable angina pectoris, myocardial infarction within ≤3 months, significant arrhythmias) and no psychiatric disorders precluding understanding of information of trial related topics and giving informed consent