Covered Versus Uncovered Metallic Stents for Malignant Biliary Obstruction Induced By Unresectable Pancreatic Cancer: Comparison with Regard to the Stent Occlusions, Biliary Complications, and Re-Interventions

Abstract

Background: It is reported that covered metallic stents (cMS) have a better patency rate than uncovered metallic stents (uMS) in distal malignant biliary stenosis. However, the biliary complications except for stent occlusions, for example, cholecystitis, sometimes spoil the quality of life of patients and require the re-interventions after insertion of cMS. We conducted this study to compare the biliary complications as well as the stent occlusions between cMS and uMS in patients with pancreatic cancer. Methods: Between March 2003 and August 2006, 29 patients had metallic stents inserted for distal malignant biliary stenosis induced by unresectable pancreatic cancer. They had chemotherapy with gemcitabine (GEM) and were followed-up for more than 3 months. The cMS were implanted in 13 patients (cMS group; Covered Wallstent n = 13) and the uMS in 16 patients (uMS group; JOSTENT n = 7, ZILVER STENT n = 9). Patient survival, stent patency, occlusion rate, complications, event-free survival (EFS), and re-interventions (i.e. endoscopic or percutaneous treatments) were analysed. Results: Overall mean follow up period after stent insertion was 325 days (range 95-1107). Patient characteristics were quite comparable in two groups. Median survival was 337 days in the cMS group and 277 days in the uMS group (p = 0.93). Median patency period was 413 days in the cMS group and 184 days in the uMS group, but no significance (p = 0.22). Occlusion rate was 31% (4/13; sludge n = 2, ingrowth n = 1, migration n = 1) in the cMS group and 63% (10/16; ingrowth n = 9, sludge n = 1) in the uMS group, but no significance (p = 0.18). Biliary complications with no relation to stent occlusions were seen more in the cMS group (23%; cholecystitis n = 2, cholangitis n = 1) than in the uMS group (0%) (p = 0.15). Median EFS was 222 days in the cMS group and 168 days in the uMS group (p = 0.70). The mean number of re-interventions per patient was almost equal between the two groups (cMS 0.9, uMS 1.0; p = 0.44). Conclusions: The cMS is superior to the uMS for the patency in patients with pancreatic cancer treated with GEM. However, considering the biliary complications and the number of re-interventions, there is no superiority between the both stents.