Plastic or metal stents for malignant stricture of the common bile duct? Results of a randomized prospective study.

The systematic use of metal stents to treat biliary obstruction is restricted by high cost compared with plastic stents. The aims of this study were to compare cost and efficacy of plastic stents and metal stents in the treatment of patients with malignant common bile duct strictures and to define factors that predict survival of these patients. One hundred eighteen patients (mean age 75 years) with malignant strictures of the common bile duct were randomized to placement of a plastic stent or metal stent. Comparisons were made with the Mann-Whitney or chi-square test as indicated; survival rates were compared with a Cox proportional hazards model. There was no significant difference in survival between the two groups. Time to first obstruction was longer for patients in the metal stent group (metal stent, median not reached vs. plastic stent, 5 months; p = 0.007). The number of additional days of hospitalization, days of antibiotic therapy, and the numbers of ERCPs and transabdominal US procedures was significantly higher in the plastic stent group. After multivariate analysis, only the presence of liver metastases was independently related to survival (p < 0.0005; OR = 2.25). This variable defined a group with a shorter survival. Median survival of patients with hepatic metastasis at diagnosis was 2.7 months compared with 5.3 months for patients without liver metastasis; in the latter group, the overall cost associated with metal stents was lower than for plastic stents. Metal stent placement is the most effective treatment of inoperable malignant common bile duct stricture. Placement of a metal stent is cost effective in patients without hepatic metastases, whereas a plastic stent should be placed in patients with spread of the tumor to the liver.