Covered self-expandable metal stents (EMS) have recently been developed to overcome tumor ingrowth.
However, there is little supporting evidence for the efficacy of covered EMS.
In this study, doctors from Japan evaluated 112 patients with unresectable distal biliary malignancies.
The patients were randomly assigned to receive either polyurethane covered or original diamond stents.
|Cumulative stent patency of covered stents was higher than that of uncovered stents.|
Overall, the team found that stent occlusion occurred in 14% of patients in the covered group, after a mean of 304 days in the covered group. This compared with 38% of patients in the uncovered group, after a mean of 166 days.
The team determined that the incidence of covered EMS occlusion was significantly lower than that of uncovered EMS.
Furthermore, the cumulative stent patency of covered stents was significantly higher than that of uncovered stents.
The team did not observe any tumor ingrowth in the covered group, whereas, this was observed in 15 patients in the uncovered group.
The doctors established that the cumulative patency of the covered EMS was significantly higher in pancreatic cancer and metastatic lymph nodes.
The team did not identify any differences in survival between the groups.
However, acute cholecystitis was observed in 2 patients in the covered group and none of the uncovered group. In addition, mild pancreatitis occurred in 5 patients in the covered group and in 1 patient in the uncovered group.
Dr Isayama and colleagues concluded, "Covered diamond stents successfully prevented tumor ingrowth and were significantly superior to uncovered stents for the treatment of patients with distal malignant biliary obstruction".
"However, careful attention must be paid to complications specific to covered self-expandable metal stents, such as acute cholecystitis and pancreatitis".