Biliary malignancy: Distal

Abstract

Self-expandable metal stents (SEMSs) have been shown to provide superior palliation for unresectable biliary obstruction when compared to plastic stents (PSs). Most studies have confirmed that SEMS patency is twice as long as that of PSs, with a decreased need for hospital readmission and endoscopic re-intervention for recurrent biliary obstruction. It has been over 10 years since a covered SEMS (CSEMS) was first introduced; however, clinical data are still insufficient to conclude that the covered SEMS is more beneficial than the bare type. Tumor ingrowth is the most common cause of occlusion in bare SEMS, whereas impaction of food or sludge is the most common cause in CSEMSs. No studies have demonstrated significant improvement in stent patency or patient survival; thus, so far, it is still controversial which type of SEMS is superior. Although SEMSs have longer stent patency than PSs, the stent occlusion rate for both covered and uncovered SEMS is between 20% and 38%. Various stent-related complications including stent migration, cholangitis, cholecystitis, pancreatitis, and hemobilia have been reported. Recently, modifications of SEMS design have been made to reduce these complications. Through these efforts, significant advances in flexibility and conformability of SEMS have reduced the rate of stent migration. In addition, phase II and III clinical trials of drug-eluting stent (DES) with antitumor effect are currently in progress. Functioning stents with improved design are expected to be available in the future. In this chapter, outcomes (plastic vs. SEMS, bare vs. covered SEMS), complications, and future of SEMS for biliary malignant obstruction are reviewed.