A Prospective Multicenter Study of a Fully Covered Metal Stent in Patients with Distal Malignant Biliary Obstruction: WATCH-2 Study.

BACKGROUND

Both fully covered (FC) and partially covered (PC) self-expandable metal stents (SEMSs) are now commercially available for distal malignant biliary obstruction (MBO). While FCSEMS can be easily removed at the time of re-interventions, it is theoretically prone to migration. However, few comparative data between FC and PC SEMSs have been reported.

AIMS

The aim of this study was to compare clinical outcomes of FCSEMS with those of PCSEMS.

METHODS

This was a multicenter, prospective study of FCSEMS for unresectable distal MBO with a historical control of PCSEMS, which was previously reported as the WATCH study. The primary outcome was recurrent biliary obstruction (RBO), and secondary outcomes were stent migration, stent removal, stent-related adverse events, and survival.

RESULTS

A total of 151 cases with unresectable distal MBO undergoing FCSEMS placement were enrolled and compared with a historical cohort of 141 cases undergoing PCSEMS placement. No significant differences were found in the rate of RBO (29 vs. 33%; P = 0.451), time to RBO (318 vs. 373 days; P = 0.382), and survival (229 vs. 196 days; P = 0.177) between FCSEMS and PCSEMS. The rate of stent migration also did not differ significantly between the two groups (14 vs. 8%; P = 0.113). The removal of FCSEMSs was successful in all 24 attempted cases (100%).

CONCLUSIONS

FCSEMSs appeared comparable to PCSEMSs in terms of RBO without a significant increase in stent migration rate in patients with unresectable distal MBO.

CLINICAL TRIAL REGISTRATION NUMBER

UMIN000007131.