Endobiliary radiofrequency ablation for malignant biliary obstruction

Percutaneous biliary drainage and radiofrequency ablation (RFA) have long been used for malignant biliary obstruction (MBO). Endoscopic radiofrequency ablation (eRFA) has been performed for this condition, and it has also been performed in combination with endoscopic biliary stenting, and/or chemotherapy. Although eRFA is apparently being used in a wide variety of applications, there are insufficient reports on its use, and mostly from retrospective studies. This article summarizes and seeks to clarify the status of RFA for MBO. eRFA for MBO with endoscopic biliary stenting was shown in a recent meta-analysis to improve overall survival (OS) at 6 months of follow-up, but there was no improvement of stent patency. A combination of eRFA and chemotherapy reportedly improved OS and progression-free survival, especially for patients with locally-advanced biliary tract cancer. When eRFA was performed for occluded self-expandable metal stents (SEMSs), the time to recurrent obstruction in the eRFA group was significantly longer than that in the patients treated by uncovered SEMS placement alone. eRFA has also been performed for inoperable ampullary tumors, and the median OS was significantly longer in an eRFA group than in a stenting alone group, and there was improvement of obstructive jaundice. eRFA reportedly has a high clinical success rate for patients after endoscopic papillectomy. Future studies should examine the synergistic effects of using immune-checkpoint inhibitors and eRFA together. eRFA has been shown to have therapeutic effects in various applications, but further large prospective research is needed to improve the level of evidence.