Comparison of plastic stents with self-expandable metal stents in palliative treatment of malignant biliary obstruction: a meta-analysis

OBJECTIVE: The present study is to compare plastic stents (PS) with self-expandable metal stents (SEMS) in patients with malignant bile duct obstruction. PATIENTS AND METHODS: Literature search in PubMed (Medline) and Embase databases was performed for all prospective randomized trials that compared SEMS with PS for the treatment of malignant biliary obstruction between January 1966 and January 2015. Research studies were included in the present meta-analysis if they met the inclusion criteria. In the meta-analysis, summary risk ratio estimates for major outcome were calculated. Forest plots were used to assess overall risk estimate, and funnel plots were used to assess overall publication bias. Meta-analysis was performed using STATA 11.0 software. RESULTS: Ten articles with 810 patients were eligible for inclusion in the present meta-analysis. SEMS is not significantly associated with complications or 30-day mortality when compared with PS (p = 0.069 and 0.167, respectively). Further stratified analysis showed similar results. For other therapeutic effects, SEMS offered 2.27-fold 6-month stent patency rate (95% CI = 1.30-3.95), and 36% reduction in a recurrent obstruction (95% CI = 0.17-0.51), as compared with PS. In addition, SEMS was associated with fewer hospitalization days than PS (p = 0.023) in a random model. With fixed model, the corresponding p-value was less than 0.001. CONCLUSIONS: The present meta-analysis demonstrates that SEMS cannot result in lower risks of complications and mortality, but can provide a lower risk of recurrent obstruction and longer stent patency for the palliation of malignant bile duct obstruction when compared with PS.