Cap-assisted endoscopic mucosal resection uses a cap affixed to the tip of the endoscope that is then positioned immediately over the target lesion. Suction is used to retract the lesion into the cap. A standard snare excision technique is then used to resect the banded lesion [12]. Resecting these lesions via EMR is often safe; however, complications may include bleeding and perforation. EMR is better suited for lesions which are superficial to the muscularis propria layer. The deep muscle layer does not suction easily into the cap, and, due to the origination of most GIST tumors in the muscularis propria layer, the EMR system may be unable to constrain the lesion. Very small tumors or GISTs originating from the muscularis mucosa layer might be approachable in this manner.

Another case series examined the efficacy of endoscopic band ligation as a method of resection of GIST. In this study, 29 patients were diagnosed with GIST by EUS and deep endoscopic biopsies. A standard endoscope with a transparent cap attached to the tip was used. The cap was placed over the lesion, suction was applied, and an elastic band was released around the base. All patients then underwent EUS every 2–3 months on schedule to visualize progression of the banding. They found that 28 GISTs sloughed completely with a mean of 4.8 weeks for complete healing. One lesion did not slough due to incomplete ligation, and when the procedure was repeated, it sloughed completely. There was one episode of bleeding that required intervention with metallic clips and no perforation events. They noted one episode of recurrence that was documented 4 months postprocedure. Of note, this approach does not allow for tumor sampling, which is a limitation given the prognostic importance of the number of mitoses [13].

A case series evaluated the efficacy and safety of endoscopic submucosal dissection (ESD) for the removal of small GISTs. GISTs were diagnosed by endoscopic ultrasonography (EUS) and managed by ESD with incision of the surrounding mucosa followed by dissection of the submucosal tissue to display the GIST, and followed finally by resection of the lesion in its entirety. Of the 20 GISTs with a mean size 1.6 cm, 19 were resected with ESD completely and 1 required additional surgery because of tumor residual in the wound after the ESD resulting in a success rate of 95 %. Of note, the mean ESD procedure time was 87.5 min. Complications included perforation in three cases after the dissection of the GIST and no delayed bleeding events [14]. The utility of ESD was also evaluated for the removal of subepithelial tumors (SETs) from the muscularis propria layer in 12 patients. An insulated-tip knife was used to remove tumor from the muscularis propria primarily. A suction and cap method (EMR-c) was used to obtain a tissue diagnosis if complete resection by ESD was not possible. A total of nine tumors were resected completely by ESD with a mean tumor size of 20.7 mm. GIST was the histological diagnosis for eight lesions and leiomyoma for four tumors. The mean procedure time was 60.9 min. There were no (?) reported perforations, bleeding or other post-procedural complications [15]. Endoscopic enucleation has also been examined in a case series of 15 patients. It is a technically difficult procedure and may lead to perforation and/or bleeding. The method utilizes an insulated-tip electrosurgical knife. Four of these patients were found to have GIST and 11 of these cases had a tumor that arose from the muscularis propria. Enucleation was successful in 14 cases with a mean procedure time of 35 min. One episode of perforation was documented in the anterior wall of the proximal gastric body and required management by endoscopic clip application [16].

A laparoscopic approach was reported in 1999 describing a gastric wedge resection for the management of GIST [17]. One major challenge with this type of resection is the determination of the appropriate resection line. Particularly for endoluminal lesions, laparoscopic visualization may not be possible. Additionally, while some gastric lesions are very accessible, tumors in areas such as the GE junction and pyloric channel pose significant challenges. For example, postoperative transformation of the stomach is a complication of excessive gastric resection with implications for long-term quality of life. From these concepts, the idea of laparoscopic and endoscopic cooperative surgery (LECS) was developed [18]. The hybrid approach to resection of GISTs merges minimally invasive laparoscopic and interventional endoscopic techniques. It is an approach that has shown to be beneficial in a highly selected subset of patients with tumors of the foregut [19]. Combined endoscopic and laparoscopic hybrid local resection was originally performed only with the intragastric resection of posterior lesions [20–22]. A larger study analyzed 52 cases of confirmed GIST within the gastric posterior wall. All patients underwent LECS without procedural complications and a median hospital stay of 5 days. There was no incidence of tumor rupture intraoperatively. One postoperative complication of anastomatic bleeding was reported. These studies suggested that a minimally invasive hybrid approach may be effective for curative treatment, with negative surgical margins and a short time to recovery.

Another study conducted reviewed seven patients who underwent LECS for the resection of gastric submucosal tumors. The purpose was to investigate the utility of hybrid laparoscopic and endoscopic techniques in the resection of gastric submucosal tumors independent of tumor location such as at the gastroesophageal junction or pyloric ring. Endoscopic submucosal dissection was used to dissect around the mucosal and submucosal layers. The seromuscular layer was then laparoscopically dissected and the tumor was removed via the abdominal cavity. All tumors were successfully removed using this approach. Of the seven tumors, two were greater than 5 cm in size and one was a confirmed GIST. The mean operation time was 169 min with negligible blood loss. There were no reported postoperative complications (Table 1).

Another series employed a hybrid approach to manage foregut mass lesions endoluminally using laparoscopic assistance. All of the lesions had been deemed to be problematic for a straightforward surgical resection. The lesions were approached endoscopically and laparoscopically. Endoscopic transection at the base of the lesions was performed with the aid of laparoscopic assistance via the serosal surface of the gastric wall. A total of seven patients underwent the hybrid approach in this study and of these patients, five underwent successful hybrid endoscopic and laparoscopic resections. There were two cases that required conversion to a larger laparoscopic resection but no conversions to open resection were required. The mean procedural time was 119 min and there were no complications [19].

The same researchers also investigated GISTs with a predominantly endophytic component. Endophytic tumors may be difficult to locate laparoscopically and as a result, a large portion of the gastric wall is often excised in order to achieve a negative margin. A push-pull technique was developed to enable resection of fourth layer tumors endoscopically followed by laparoscopic resection of the resection site to obtain a negative margin. In this series, four patients in two institutions underwent the push-pull hybrid procedure where an endoscopic resection of the tumor was performed with laparoscopic assistance (push) followed by full-thickness laparoscopic resection of the base with endoscopic assistance (pull). While the endoscopic resection alone was associated with a positive deep margin, the push-pull hybrid technique allowed for complete R0 resections. In this study, endophytic GISTs in anatomically challenging locations could be safely and effectively managed using an oncologically sound, minimally invasive approach [11].

Another hybrid technique utilizing EGD and thorascopy for the management of GISTs originating in the thoracic esophagus has been described. Whereas the conventional transthoracic approach is highly invasive, the hybrid approach provided a minimally invasive alternative. They identified four tumors, one of which was confirmed to be GIST. The resection plane between the tumor and the mucosal layer of the esophagus was first identified. This was accomplished using a sodium hyaluronate solution stained with indigo carmine. Using EGD, it was injected into the submucosa. Following this, using three-port thorascopy, the tumor was enucleated using the dyed submucosa as a guide, thus minimizing the risk of full-thickness perforation of the esophagus. The muscle layer was then sutured and the tumor was removed. The mean surgical time was 137.7 min and mean blood loss was 21.2 ml. No perioperative complications were reported. This procedure was performed using three access ports, and was felt to reduce postoperative pain and hasten early postoperative recovery [23].