Covered versus uncovered metal stents for malignant gastric outlet obstruction : A systematic review and meta-analysis of RCTs

Background and aim: Self expandable metal stent are used for palliation of malignant gastric outlet obstruction (GOOD) in patients with gastric or pancreatic malignancy. Studies comparing C-SEMS and U-SEMS have led to inconclusive results. To date only a previous meta-analysis assessing together prospective and randomized studies with statistical criticism was published. Aims: comparing efficacy and safety of FCSEMS vs USEMS in patients with GOOD. Material and methods: A computerized medical search was performed by using MEDLINE, EMBASE, Cochrane Library, from 2000 to September 2017 aimed at identifying available randomized trials comparing C-SEMS versus U-SEMS in patients with GOOD. Primary outcomes were stent survival and patient survival, while secondary outcomes were clinical and technical success, adverse events, stent occlusion and migration Pooled estimates were computed using the random effects models. Results: Overall 7 RCTs were identified including 635 patients were included. Stent and patient survival did not statistically significantly differ between C-SEMS and U-SEMS groups (HR=0.93, 95% CI: 0.66–1.31; HR=0.87, 95% CI: 0.64–1.19, respectively). Clinical success and technical success were not statistical difference between two groups (OR=1.44 95%, CI: 0.68–3.05, OR=1.17, 95% CI: 0.39–3.52). U-SEMS was associated with lower risk of adverse events (OR=2.20, 95% CI: 1.37–3.54) but with higher risk of tumor ingrowth (OR=0.30, 95% CI: 0.18–0.49). C-SEMS was associated with higher risk of migration (OR=5.24, 95% CI: 2.26–2.12). Conclusions: C-SEMS did not show statistically significant differences in terms of stent and patient survival as compared to U-SEMS although U-SEMS was associated with higher risk of tumor ingrowth and C-SEMS with migration. Further studies using new C-SEMS with anti migration system are needed.