Endoscopic placement of covered versus uncovered self-expandable metal stents for palliation of malignant gastric outlet obstruction

Abstract

Objective: Stenting is an established endoscopic therapy for malignant gastric outlet obstruction (mGOO). The choice of stent (covered vs uncovered) has been examined in prior randomised studies without clear results.

Design: In a multicentre randomised prospective study, we compared covered (CSEMS) with uncovered self-expandable metal stents (UCSEMS) in patients with mGOO; main outcomes were stent dysfunction and patient survival, with subgroup analyses of patients with extrinsic and intrinsic tumours.

Results: Overall survival was poor with no difference between groups (probability at 3 months 49.7% for covered vs 48.4% for uncovered stents; log-rank for overall survival p=0.26). Within that setting of short survival, the proportion of stent dysfunction was significantly higher for uncovered stents (35.2% vs 23.4%, p=0.01) with significantly shorter time to stent dysfunction. This was mainly relevant for patients with extrinsic tumours (stent dysfunction rates for uncovered stents 35.6% vs 17.5%, p<0.01). Subgrouping was also relevant with respect to tumour ingrowth (lower with covered stents for intrinsic tumours; 1.6% vs 27.7%, p<0.01) and stent migration (higher with covered stents for extrinsic tumours: 15.3% vs 2.5%, p<0.01).

Conclusions: Due to poor patient survival, minor differences between covered and uncovered stents may be less relevant even if statistically significant; however, subgroup analysis would suggest to use covered stents for intrinsic and uncovered stents for extrinsic malignancies.

Keywords: gastrointesinal endoscopy; stents.

Figure 1

Covered and uncovered self-expandable metallic stent (SEMS) used in this study. (A) The covered SEMS has an antimigration system at both ends (proximal uncovered flare and distal uncovered area). (B) The uncovered SEMS is straight and contains no membrane.

Figure 2

CONSORT (Consolidated Standards of Reporting Trials) flow diagram of patient enrolment. CSEMS, covered self-expandable metal stent; GOO, gastric outlet obstruction; UCSEMS, uncovered self-expandable metal stent.

Figure 3

Kaplan-Meier curves for patient survival. The survival probability at 1, 2 and 3 months was 85.1%, 66.6% and 49.7% in the covered self-expandable metal stent (CSEMS) group and 85.8%, 64.5% and 48.4% in the uncovered self-expandable metal stent (UCSEMS) group, respectively (log-rank p=0.26).

Figure 4

Kaplan-Meier curves for stent dysfunction (SD). (A) Kaplan-Meier curves for SD among overall patients. The probability of no SD at 1, 2 and 3 months was 83.3%, 75.6% and 69.1% in the CSEMS group and 92.2%, 88.3% and 83.7% in the UCSEMS group, respectively (log-rank p<0.01). (B) Kaplan-Meier curves for SD among patients with extrinsic tumours. The probability of no SD at 1, 2 and 3 months was 84.1%, 76.2% and 70.4% in the CSEMS group and 92.3%, 88.2% and 85.9% in the UCSEMS group, respectively (log-rank p<0.01). (C) Kaplan-Meier curves for SD among patients with intrinsic tumours. The probability of no SD at 1, 2 and 3 months was 82.1%, 74.5% and 67.1% in the CSEMS group and 92.2%, 88.6% and 81.1% in the UCSEMS group, respectively (log-rank p=0.14).