Introduction

Gastric Gastrointestinal Stromal Tumors (GISTs) are among the most common mesenchymal tumors arising in the gastrointestinal tract. Despite many international guidelines, the treatment of GISTs with tumor diameters less than 50 mm remains controversial. Although surgical resection is indicated for histologically diagnosed GISTs, endoscopic resection has recently been reported. However, endoscopic resection, mainly Endoscopic submucosal dissection (ESD), often requires a full-layer resection of the gastric wall, which requires extensive suturing. Therefore, we have developed an ESD technique for endoscopic resection of the gastric wall that uses a threaded clip and a detachable snare to strangulate the muscle layer prior to resection and allows safe and easy complete resection without perforation (EISMR: Endoscopic inversion and strangulation of the muscle layer and resection). We now report seven cases of EISMR for gastric GISTs.

Aims & Methods

We evaluated the safety and efficacy of EISMR for GISTs. Seven gastric GISTs (4 males and 3 females) with tumor diameters of 50 mm or less for which we performed EISMR were included in this study, and the en bloc resection rate, R0 resection rate, procedure time, and complications were investigated. All patients underwent EUS and abdominal CT scan before treatment to confirm that the pathological diagnosis was GIST, that the tumor diameter was less than 50 mm, and that the tumor was intraluminal growth type.
In the EISMR procedure, sodium hyaluronate solution was first injected into the submucosal layer of the lesion to dissect the submucosa as in ESD. After a yellowish GIST continuity with the muscularis propria is observed, the submucosa and muscle layer are dissected to expose as much of the submucosa as possible without damaging the tumor. Next, a threaded clip is attached to the tumor and pulled in order to invert the muscle layer. The muscle layer is then retracted into the gastric lumen to form a polyp-like shape, and the base of the muscle layer is strangulated using an detachable snare (PolyLoop Ligating Device, Olympus). The upper margin of the strangulated area is then incised to complete the resection. After confirming that there is no perforation, the strangulated area is additionally sutured with a clip.

Results

All seven cases could be resected en bloc, with a median time of 90.5 minutes (58-120). Of the seven EISMR cases, five cases were performed by experts and two by non-experts. All patients were discharged on postoperative day 5 or 6 without adverse events. Pathology results showed complete resection in the low-risk GIST group. Upper endoscopy 3-6 months after EISMR showed no tumor recurrence and only scarring.

Conclusion

EISMR for gastric GISTs is potentially safe, easy and useful without excessive invasion.