Endoscopic radiofrequency ablation for ingrowth occlusion after bilateral metal stent placement for malignant hilar biliary obstruction: a prospective pilot study

Abstract

Endoscopic biliary radiofrequency ablation (RFA) may be an option for the treatment of ingrowth occlusion after self-expandable metal stent (SEMS) deployment; however, its utility remains uncertain. This study aimed to examine the feasibility of RFA for the palliation of ingrowth after bilateral SEMS placement in patients with malignant hilar biliary obstruction. This prospective, single-center, pilot study enrolled 30 patients who met the eligibility criteria between April 2020 and March 2022. Study outcomes were technical success, clinical success, recurrent biliary obstruction (RBO), and adverse events (AEs) besides RBO associated with RFA for ingrowth occlusion. Furthermore, factors predictive of clinical success were evaluated. Technical and clinical success rates were 93.3% (28/30) and 71.4% (20/28), respectively. The rates of early and late AEs were 6.7% (2/30) and 10.0% (2/20), respectively. The incidence rate of RBO after RFA was 45.0% (9/20), and the median time to RBO was 163 days. Multivariate analysis of the factors affecting clinical success revealed a positive association between the recanalization diameter on the ingrown part within the SEMS (odds ratio, 1.13; 95% confidence interval, 1.01-1.26; P= .038). The calculated optimal cutoff for the ratio of the recanalization diameter to the SEMS diameter for predicting clinical success was 51.1%. Endoscopic biliary RFA elicited promising results, with good long-term stent patency and without the requirement of any additional stent placement, for the palliation of ingrowth occlusion after bilateral SEMS placement. However, the clinical success rate was insufficient, necessitating improvements in the future. (Clinical trial registration number: UMIN000040154.).