The selection and strategy of stents in endoscopic drainage of unresectable perihilar cholangiocarcinoma: a meta-analysis

Endoscopic biliary drainage serves as the primary palliative intervention for malignant hilar biliary obstruction (MHBO), especially unresectable perihilar cholangiocarcinoma (pCCA), with metal stents (MS) and plastic stents (PS) constituting the main therapeutic modalities. Despite widespread clinical adoption, persistent equipoise surrounds their comparative therapeutic efficacy, with current guidelines lacking consensus on optimal deployment strategies. Therefore, this study included the recent studies of endoscopic stent therapy for unresectable pCCA to explore further the drainage effect and postoperative complications of the two stents, and to provide clinical guidance for the selection of stent drainage. For unresectable pCCA, biliary drainage is the basis for subsequent systemic treatment and also one of the essential therapeutic methods for prolonging survival time. Endoscopic drainage has the advantages of less pain and better compliance with physiology compared with percutaneous transhepatic biliary drainage (PTBD). However, due to the difficulty of endoscopic treatment operation and the possibility of inducing biliary tract infection, especially for Bismuth-Corlette type III and above pCCA, endoscopic treatment is more challenging. Currently, there are still many controversial issues regarding the selection of stents and drainage strategies in endoscopic biliary drainage. This meta-analysis systematically evaluates contemporary evidence to establish evidence-based protocols for stent selection in MHBO, especially pCCA. A comprehensive search of multiple databases (Pubmed, MEDLINE, Embase, Cochrane) and grey literature was conducted, covering articles from the inception of the databases until September 2024, without restrictions on publication year or language, provided they included at least an English abstract. Studies comparing MS and PS techniques through endoscopic retrograde cholangiopancreatography (ERCP) were included. Outcomes analyzed included technical and clinical success, complications, stent patency, and re-intervention rates. Meta-analysis was conducted using RevMan software, STATA 17.0, and R software on the data of interest extracted from the selected studies. A total of 10 cohort studies and two randomized controlled trials (RCT) were included, assessing 1 405 patients (714 patients in the MS group and 691 patients in the PS group). MS demonstrated comparable technical success rates risk ratio (RR) = 1.00; 95% confidence interval (CI) 0.97–1.04, I2 = 0%, p = 0.82 and clinical success rates RR = 0.99; 95%CI 0.93–1.06, I2 = 1%, p = 0.75 to PS. MS exhibited superior stent patency hazard ratio (HR) = 2.11; 95% CI 1.31–3.39, I2 = 0%, p = 0.002 with 68% reduction in stent occlusion odds ratio (OR) = 2.89; 95% CI 2.08–4.03, I2 = 0%, p < 0.00001 to PS. Complication profiles significantly favored MS to PS: 63% lower cholangitis incidence OR = 3.61; 95% CI 2.46–5.30, I2 = 32%, p < 0.00001; 87% reduction in stent migration OR = 7.87; 95% CI 2.56–24.17, I2 = 0%, p < 0.0003; 68% fewer reintervention OR = 3.17, 95% CI 2.37–4.23, I2 = 22%, p < 0.00001. No significant differences emerged in pancreatitis OR = 0.96; 95%CI 0.57–1.61, I2 = 1%, p = 0.87, hemorrhage OR = 1.29, 95%CI 0.41–4.04, I2 = 0%, p = 0.66, or survival HR = 1.01; 95%CI 0.91–1.12, I2 = 0%, p = 0.894. This meta-analysis establishes MS as the preferential modality for endoscopic MHBO management, demonstrating 2.1-fold longer patency duration and 63–87% risk reduction in major complications compared to PS. These findings strongly support protocolized MS deployment in unresectable pCCA, particularly for reducing cholangitis burden and reintervention frequency.