Comparison of efficacy between uncovered and covered self-expanding metallic stents in malignant large bowel obstruction: a systematic review and meta-analysis

Aim Insertion of a self-expandable metallic stent (SEMS) can rapidly relieve colorectal obstruction. This study aimed to compare the efficacy between uncovered and covered SEMSs in the treatment of malignant colorectal obstruction. Method A systematic search in Medline, Embase, the Cochrane controlled trials register and bibliographies of retrieved articles was performed. Randomized controlled trials and other comparative studies comparing uncovered and covered SEMSs for treatment of malignant colorectal obstruction were selected for this systematic review and meta-analysis. The main outcome measures were technical success, clinical success, tumour ingrowth, tumour overgrowth, early migration (= 7 days), late migration (> 7 days), overall complications and the duration of stent patency. Results Compared with covered SEMSs, uncovered SEMSs were associated with a lower late migration rate (relative risk 0.25; 95% CI 0.08, 0.80; P = 0.02), a higher tumour ingrowth rate (relative risk 5.99; 95% CI 2.23, 16.10; P = 0.0004) and a prolonged stent patency (weighted mean difference 15.34 days; 95% CI 4.31, 26.37; P = 0.006). There was no significant difference in technical success, clinical success, tumour overgrowth, early migration, perforation or overall complications between the two groups. Conclusion Tumour ingrowth occurred more frequently in the uncovered SEMS group, while late migration was more common in the covered SEMS group.