Malignant distal biliary obstruction is a frequent complication of advanced pancreatic and biliary tract cancers. Endoscopic placement of self-expandable metal stent (SEMS) is the standard treatment, but dysfunction occurs in 19–40% of cases. The optimal management after SEMS occlusion remains unclear. The aim of this study was to assess and compare three types of second biliary stents (plastic (PS), covered SEMS (CSEMS) and uncovered SEMS (USEMS)) for treatment of primary SEMS occlusion in malignant distal biliary obstruction.

We conducted a multicenter retrospective study in three hospital centers. All patients suffering from malignant distal biliary obstruction and treated for SEMS occlusion between January 2012 and December 2023 were enrolled. Patients with hilar obstruction or benign disease were excluded. All second stents were placed endoscopically using a “stent-in-stent” transpapillary technique. Stent obstruction, stent lifespan and overall survival were compared in patients with PS, CSEMS and USEMS. A competing risk analysis was performed to estimate the cumulative incidence of stent obstruction, taking into account death and surgery as competing events.

A total of 142 patients (median age 71.2; 64% male) were included; PS, CSEMS and USEMS were placed in 42, 40 and 60 patients, respectively. Pancreatic cancer was the most common diagnosis (70.4%). Median time to stent obstruction did not differ significantly between groups, but occlusion rates were lower in the CSEMS group (25%) than in the PS (59.5%) or USEMS groups (45%) (p = 0.007). This result was confirmed in the competing risk analysis. In multivariable analysis, stent type was the only independent predictor of obstruction, with PS (SHR= 3.76, p = 0.004; ref: CSEMS) and USEMS (SHR=2.32, p = 0.042) associated with stent obstruction. Median overall survival was 157 days and did not differ between groups, but was significantly lower in patients with metastatic disease, best supportive care, and higher bilirubin levels. Adverse event rates were low and similar across groups.

As new chemotherapy protocols increase survival of patients with pancreatic cancer and cholangiocarcinoma, the issue of managing biliary stent obstruction is crucial. This study is the largest series evaluating the type of second biliary stent following obstruction of a first SEMS and provides important insights. Compared to USEMS or PS, using CSEMS reduces the risk of second stent occlusion in patients with malignant distal biliary obstruction treated by trans papillary drainage. Second stent type was the only significant predictor of obstruction but did not improve patient overall survival which was mainly determined by the underlying malignant disease.