Which types of stent, uncovered or covered, should be used in gastric outlet obstructions?

Self-expandable metallic stents (SEMS) have been widely used in inoperable malignant gastric outlet obstructions, but stent obstructions caused by tumor ingrowth and migration are a major problem of SEMS. The aims of this study were to assess the rate of stent restenosis, to identify lesion characteristics related to early restenosis by tumor ingrowth, and, in particular, to find suitable patient groups for uncovered or covered stents at first implantation.

Forty-nine patients were reviewed: stomach cancer in 34 patients, primary duodenal cancer in 3 patients, pancreatic cancer in 5 patients, and common bile duct cancer in 7 patients. In principle, uncovered stents were initially placed at the time when obstruction symptoms occurred and the endoscope would not pass through. Stent obstruction due to tumor ingrowth within 4 weeks after the first stent implantation was regarded as early stent restenosis.

Technical success was seen in 49/49 patients (100%). Migration did not occur. Stent obstructions caused by tumor overgrowth were found in 2/49 patients (4.1%) after 1 month. Stent obstructions caused by tumor ingrowth occurred in 14/49 patients (28.5%), and 7 of them (14.3%) were found to have early restenosis. The only statistically significant factor for early restenosis was stenosis site, and early restenosis was more frequent in the postoperative anastomosis site in the current study; a) 2/18 antropyloric obstructions (11.1%), b) 1/15 pyloric and duodenal bulb obstructions (6.7%), c) 0/10 duodenal second portion obstructions (0%), and d) 4/6 postoperative anastomosis site obstructions (66.7) (P < 0.05, 95% CI 0.003-0.005).

Uncovered stents are technically feasible and effective for most malignant gastric outlet obstructions. However, because of frequent early restenosis among patients with postoperative anastomosis site obstructions, the placement of covered or simultaneous dual stents to prevent early restenosis should be considered when stenting postoperative anastomosis site obstructions.