Endoscopic Stenting for Malignant Hilar Biliary Obstruction: Should It Be Metal or Plastic and Unilateral or Bilateral?

Background: Endoscopic biliary drainage is the palliative treatment of choice for malignant biliary hilar obstruction. There are conflicting opinions as to whether stents should be plastic or metal and whether stents should be unilateral or bilateral.

Aim: To systematically review the literature on optimal endoscopic management of malignant hilar biliary obstruction.

Methods: A comprehensive search of several databases was carried out. A fixed-effect or a random-effect model was used to pool the data according to the result of a statistical heterogeneity test.

Results: Ten trials were enrolled. Compared with plastic stents, the use of metal stents was associated with a significantly higher successful drainage rate [odds ratio (OR) 0.26; 95% confidence interval (CI) 0.16-0.42; I2=40.3%], lower early complication rate (OR 2.92; 95% CI 1.65-5.17; I2=0%), longer stent patency [hazard ratio (HR) 0.43; 95% CI 0.30-0.61; I2=57.6%], and longer patient survival (HR 0.73; 95% CI 0.56-0.96; I2=56.9%). The unilateral biliary drainage group achieved a significantly higher successful stent insertion rate compared with the bilateral drainage group (OR 3.44; 95% CI 1.91-6.19; I2=0%), whereas no difference was observed between groups with respect to successful drainage rate (OR 1.73; 95% CI 0.89-3.37; I2=0%), early complications (OR 0.96; 95% CI 0.18-5.13; I2=60.4%), late complications (OR 1.41; 95% CI 0.54-3.67; I2=70.4%), stent patency (HR 0.57; 95% CI 0.19-1.73; I2=91.1%), and patient survival (HR 0.75; 95% CI 0.31-1.80; I2=94.3%).

Conclusion: The performance of metallic stents was superior to that of plastic stents for hilar tumor palliation. Unilateral biliary drainage may be as effective as bilateral drainage for patients with hilar biliary obstruction.