Comparison of noncovered and covered metal stents for the endoscopic palliation of distal malignant biliary obstruction

Background: Endoscopic placement of self-expandable metallic stents (SEMS) is considered as a standard therapeutic option to relieve symptomatic cholestasis in patients (pts) with unresectable pancreato-biliary malignancies. The main late complication of noncovered SEMS (NCSEMS) is tumor ingrowth through the bare metal mesh leading to stent occlusion. Using covered SEMS (CSEMS) theoretically may reduce this complication. The objective of this retrospective study to compare the efficacy and safety of NCSEMS and CSEMS in a cohort of pts with unresectable malignant distal biliary strictures. Patients and Methods: During the period of 2005 January and 2007 December,61pts (mean age=71, m/f=31/30) who have been treated by NCSEMS [n=34 (55%)] or CSEMS [n=27 (45%)] placement, and with adequate follow-up data were included into the study. Pancreatic cancer (77%) consisted of the vast majority of causes of biliary obstruction. The primary outcome variables were the overall survival time and the duration of stent patency. Secondary outcomes included the rates of early, late complications and reinterventions. Results: The median stent patency times showed no significant difference between NCSEMS and CSEMS groups [120 (3–730) and 150 (7–240) days], respectively. The median survival times was 120 (3–800) days in NCSEMS and 150 (7–300) days CSEMS groups. The rates of early complications were 16 and 14% in NCSEMS and CSEMS groups, respectively. Late complication such as tumor ingrowth occured more frequently in NCSEMS as compared to CSEMS group (20.6 vs. 0%, p=0.019). Contrary, tumor overgrowth observed in 11% in CSEMS and 0% in SEMS groups (p=0.019). Endoscopic reintervention was performed for stent dysfunction in 14 and 11% at a median 365(60–400) and 245 (240–420) days after the index procedure in the NCSEMS and CSEMS groups, respectively. Conclusions: Based on the results of the present study, no differences were observed between patency rates of NCSEMS and CSEMS. Survival times and the overall complication rates showed no differences between the two groups.