Intraductal endoscopic radiofrequency ablation for the treatment of hilar non-resectable malignant bile duct obstruction

Abstract

Aim: To evaluate the safety and technical success of endoscopic radiofrequency ablation (RFA) for palliative treatment of malignant hilar bile duct obstruction.

Methods: In this study, a recently CE and FDA-approved endoscopic RFA catheter was first tested in an ex vivo pig liver model to study the effect of electrosurgical variables on the extent of the area of induced necrosis. Subsequently, a retrospective analysis was conducted of all patients treated with endoscopic RFA for malignant biliary obstruction at our center between February 2012 and April 2013. All patients received an additional plastic stent implantation into the biliary tree following RFA.

Results: In the pig model, ablation time of 60-90 seconds using the bipolar soft coagulation mode at 8-10 watts with an effect of 8 was found to be the most feasible setting. Twelve patients (5 females, 7 males; mean age, 70 years) underwent 19 endoscopic RFA (range, 1-5) sessions. Deployment of RFA was successful in all patients. Systemic chemotherapy was administered in four patients. We observed biliary bleeding 4-6 wk after the intervention in three cases and two of these patients died: in one patient, spontaneous hemobilia occurred, whereas bleeding started during stent extraction in the other. In the third patient, bleeding was stopped by insertion of a non-covered self-expanding metal stent. Another three patients developed cholangitis during follow-up. Seven patients died during follow-up and median survival was 6.4 mo (95%CI: 0.05-12.7) from the time of the first RFA.

Conclusion: Endoscopic RFA is an easy to perform and technically highly successful procedure. However, hemobilia possibly associated with RFA occurred in three of our patients. Therefore, larger prospective studies are needed to further evaluate the safety and efficacy of this promising new method.

Keywords: Bile duct cancer; Cholangiocarcinoma; Cholangiography; Endoscopic retrograde cholangiopancreatography; Endoscopy; Radiofrequency ablation.

Figure 1

The radiofrequency ablation probe Habib EndoHPB (EMcision United Kingdom, London, United Kingdom) features two ring electrodes at the tip that are 8 mm apart. The probe is designed to perform bipolar cautery in endoscopic surgical procedures.

Figure 2

Exemplary results from the ex vivo pig liver model. From left to right, higher watt variables were used. Necrotic areas are marked by a arrow.

Figure 3

Results from the ex-vivo pig liver model. A: Length; B: Width. Varying electrosurgical variables revealed distinct differences in the extent of necrotic area. The used combinations are explained in the legend. e.g., the blue column shows length and width of the necrosis caused by RFA with 14 watt, effect 8 with an ablation time of 90 s. RFA: Radiofrequency ablation.

Figure 4

Application of endoscopically guided, intraductal radiofrequency ablation in a 72-year-old patient with an extended perihilar cholangiocarcinoma (Klatskin tumor, stage Bismuth IV, histologically proven) involving all subsegments. Multisegmental radiofrequency ablation (RFA) applications were performed (from left above to lower right). The patient experienced no treatment-associated complications and was doing well 15 mo after the initiation of endoscopic RFA treatment.

Figure 5

Kaplan-Meier survival curve of all study patients (n = 12). Calculation of survival started at the time of the first endoscopic radiofrequency ablation treatment in each patient.