Clinical Outcomes of Inside Stents and Conventional Plastic Stents as Bridge-to-Surgery Options for Malignant Hilar Biliary Obstruction.

BACKGROUND: The appropriate method of preoperative endoscopic biliary drainage (EBD) for cholangiocarcinoma with hilar biliary obstruction remains controversial. The inside-stent technique is a method of placing plastic stents entirely inside the bile duct. Several studies of patients with unresectable stage have reported longer stent patency compared with conventional endoscopic biliary stenting (EBS). Inside-stent techniques have been introduced as a bridge-to-surgery option and as an alternative to conventional EBS. AIMS: We aimed to evaluate the clinical outcomes of inside stent use and conventional EBS. METHODS: During this retrospective multicenter study, we reviewed consecutive patients with cholangiocarcinoma who underwent radical surgery after conventional EBS or inside-stent insertion. Adverse event (AE) rates after EBD and post-surgical AEs were compared. A multivariable analysis was performed to identify factors affecting cholangitis after EBD. RESULTS: Conventional EBS and inside-stent procedures were performed for 56 and 73 patients, respectively. Patient backgrounds were similar between groups, except for percutaneous transhepatic portal vein embolization. The waiting time before surgery was similar between groups (28.5 days vs. 30 days). There were no significant differences in the cholangitis rate (21.4% vs. 26.0%; P = 0.68) and all AEs (25.0% vs. 30.1%; P = 0.56) between groups. The post-surgical AE rate was similar between the groups. The multivariable analysis found that preprocedural cholangitis was a risk factor for cholangitis after EBD (odds ratio: 5.67; 95% confidence interval: 1.61-19.9). CONCLUSIONS: The outcomes of inside-stent techniques and conventional EBS for the management of preoperative EBD are comparable for patients with cholangiocarcinoma.

WONDER-02: plastic stent vs. lumen-apposing metal stent for endoscopic ultrasound-guided drainage of pancreatic pseudocysts-study protocol for a multicentre randomised non-inferiority trial.

BACKGROUND: Endoscopic ultrasound (EUS)-guided transluminal drainage has become a first-line treatment modality for symptomatic pancreatic pseudocysts. Despite the increasing popularity of lumen-apposing metal stents (LAMSs), plastic stents may resolve non-necrotic fluid collections effectively with lower costs and no LAMS-specific adverse events. To date, there has been a paucity of data on the appropriate stent type in this setting. This trial aims to assess the non-inferiority of plastic stents to a LAMS for the initial EUS-guided drainage of pseudocysts. METHODS: The WONDER-02 trial is a multicentre, open-label, non-inferiority, randomised controlled trial, which will enrol pancreatic pseudocyst patients requiring EUS-guided treatment in 26 centres in Japan. This trial plans to enrol 80 patients who will be randomised at a 1:1 ratio to receive either plastic stents or a LAMS (40 patients per arm). In the plastic stent group, EUS-guided drainage will be performed using two 7-Fr double pigtail stents. In the LAMS group, the treatment will be performed in the same way except for LAMS use. The step-up treatment will be performed via endoscopic and/or percutaneous procedures at the trial investigator's discretion. The primary endpoint is clinical success, which is defined as a decrease in a pseudocyst size to ≤ 2 cm and an improvement in inflammatory indicators (i.e. body temperature, white blood cell count, and serum C-reactive protein). Secondary endpoints include technical success, adverse events including mortality, pseudocyst recurrence, and medical costs. DISCUSSION: The WONDER-02 trial will investigate the efficacy and safety of plastic stents compared to a LAMS in EUS-guided treatment of symptomatic pancreatic pseudocysts with a particular focus on the non-inferior efficacy of plastic stents. The findings will help establish a new treatment algorithm for this population. TRIAL REGISTRATION: ClinicalTrials.gov NCT06133023 registered on 9 November 2023. UMIN000052647 registered on 30 October 2023. jRCT1032230444 registered on 7 November 2023.