Percutaneous transhepatic or endoscopic ultrasound-guided biliary drainage in malignant distal bile duct obstruction using a metal stent: study protocol for a prospective European multicentre trial (PUMa trial)

<strong>Abstract:</strong> <strong>Background</strong> Percutaneous transhepatic biliary drainage [PTBD] is still universally used in patients with malignant distal bile duct obstruction when endoscopic retrograde cholangiopancreatography [ERCP] is not successful or not possible to perform. However, endoscopic ultrasound-guided biliary drainage [EUS-BD] was associated with better clinical success and a lower rate of adverse events (AE) in recent comparative studies, although further improvements in the PTBD technique, such as primary stent implantation as a one-step procedure, percutaneous ultrasound-guided bile duct puncture and left-sided bile duct access, were not considered. The aim of this study is to compare both procedures carried out as intended one-step procedures with primary metal stent insertion. <strong>Methods</strong> The PUMa trial is an ongoing European non-randomized, controlled, parallel group, non-inferiority multicentre trial. Fourteen study centres perform only one of the two procedures with regard to the best local experience. PTBD is performed as a one-step procedure with primary metal stent insertion after percutaneous ultrasound-guided bile duct access. EUS-BD is performed as a one-step procedure using the EUS-guided trans-gastric or trans-duodenal access route for trans-gastric trans-hepatic (EUS-HGS), trans-duodenal (EUS-CDS) or antegrade trans-papillary (EUS-AGS) metal stent insertion. The main target values are the technical and clinical success rates, AEs within 30 days and overall disease-specific survival within 6 months. The calculated total number of cases is 212 patients. <strong>Discussion:</strong> The PUMa trial investigates whether PTBD is not inferior to EUS-BD in terms of technical and clinical success if primary metal stent insertion is performed as a one-step procedure in both procedures. Differences are expected in the quantity and variety of AEs, number of re-interventions and length of hospital stay. <strong>Trial Registration</strong>: ClinicalTrials.gov ID: NCT03546049 (date of registration 22.05.2018)