Biliary drainage in inoperable malignant biliary distal obstruction: A systematic review and meta-analysis

BACKGROUND: Endoscopic drainage remains the treatment of choice for unresectable or inoperable malignant distal biliary obstruction (MDBO). AIM: To compare the safety and efficacy of plastic stent (PS) vs self-expanding metal stent (SEMS) placement for treatment of MDBO. METHODS: This meta-analysis was developed according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A comprehensive search was performed in MEDLINE, Cochrane, Embase, Latin American and Caribbean Health Sciences Literature, and grey literature to identify randomized clinical trials (RCTs) comparing clinical success, adverse events, stent dysfunction rate, reintervention rate, duration of stent patency, and mean survival. Risk difference (RD) and mean difference (MD) were calculated and heterogeneity was assessed with I(2) statistic. Subgroup analyses were performed by SEMS type. RESULTS: Twelve RCTs were included in this study, totaling 1005 patients. There was no difference in clinical success (RD = -0.03, 95% confidence interval [CI]: -0.01, 0.07; I(2 )= 0%), rate of adverse events (RD = -0.03, 95%CI: -0.10, 0.03; I(2 )= 57%), and mean patient survival (MD = -0.63, 95%CI: -18.07, 19.33; I(2) = 54%) between SEMS vs PS placement. However, SEMS placement was associated with a lower rate of reintervention (RD = -0.34, 95%CI: -0.46, -0.22; I(2) = 57%) and longer duration of stent patency (MD = 125.77 d, 95%CI: 77.5, 174.01). Subgroup analyses revealed both covered and uncovered SEMS improved stent patency compared to PS (RD = 152.25, 95%CI: 37.42, 267.07; I(2) = 98% and RD = 101.5, 95%CI: 38.91, 164.09; I(2) = 98%; respectively). Stent dysfunction was higher in the covered SEMS group (RD = -0.21, 95%CI: -0.32, -0.1; I² = 205%), with no difference in the uncovered SEMS group (RD = -0.08, 95%CI: -0.56, 0.39; I² = 87%). CONCLUSION: While both stent types possessed a similar clinical success rate, complication rate, and patient-associated mean survival for treatment of MDBO, SEMS were associated with a longer duration of stent patency compared to PS.