AGA Tech Summit

Therapeutic endoscopy expands reach to deep GI lesions



Endoscopic resection of gastrointestinal tumors arising from the muscularis propria is feasible, but the techniques are challenging and require a sure hand with closure techniques.

“The main difficulty with these procedures is closure,” Mouen A. Khashab, MD, said at the AGA Tech Summit, which was sponsored by the AGA Center for GI Innovation and Technology. “Sometimes you can create a large defect that you’re not sure you can close. You must have experience with large defect closure.”

In experienced hands, the endoscopic approaches spare adjacent large organs, have a complete resection rate approaching 95%, and an acceptable rate of adverse events. They can provide excellent surgical specimens that are more than adequate for histologic studies, although some cannot provide any information on margins, said Dr. Khashab, director of therapeutic endoscopy at Johns Hopkins University, Baltimore. “When doing a full-thickness endoscopic resection, you can’t comment on the margins. You’re not getting any normal tissue around the tumor, and this can create an issue with some patients.”

Dr. Khashab briefly described three endoscopic resection techniques that are suitable for the following deep GI tumors:

  • Submucosal tunneling endoscopic resection. STER is most suitable for smaller tumors (4 cm or less). Tumors of this size are easily removed en bloc via the endoscopic tunnel. Larger tumors can also be resected this way, but need to be removed piecemeal after dissection off the muscle layer. This is an acceptable alternative in leiomyomas but not in gastrointestinal stromal tumors. “For this technique, you introduce the scope into the submucosal layer and create a space with tunneling,” Dr. Khashab said. “We then expose the tumor, dissect it off the wall of the muscularis propria, and pull it out of the tunnel.” A 2017 meta-analysis examined outcomes in 28 studies with data on 1,085 lesions. The pooled complete resection and en bloc resection rates were 97.5% and 94.6%, respectively. Common complications associated with STER were air leakage symptoms (15%) and perforation (5.6%). “The perforation rate is reasonable, I think. A lot of these complications can be managed intraoperatively with clipping or suturing,” Dr. Khashab noted.
  • Endoscopic submucosal dissection: ESD is now being used to resect tumors that originate from the muscularis propria. “This is something I didn’t used to think was even possible,” Dr. Khashab said. “But we are seeing some literature on this now. A lot of these tumors originate from the superficial MP [muscularis propria], so we can dissect off the muscle without needing a full-thickness resection.” He presented findings from a large study comprising 143 patients with submucosal gastric or esophageal tumors that arose from the muscularis propria at the esophagogastric junction. These were large lesions, a mean 17.6 cm, but they ranged up to 50 cm. The en bloc resection rate was 94%. There were six perforations (4%), along with four pneumoperitoneum and two pneumothorax, which resolved without further surgery. There were no local recurrences or metastases when the 2012 study appeared, with a mean follow-up of 2 years.
  • Endoscopic full-thickness resection: EFTR “is a technically demanding procedure, and we frequently have to work on these tumors in retroflexion,” Dr. Khashab said. He referred to a 2011 paper, which described the EFTR technique used in 26 patients with gastric cancers. The tumors (mean size, 2.8 cm) were located in the gastric corpus and in the gastric fundus. Although the procedures were lengthy, ranging from 60 to 145 minutes, they were highly successful, with a 100% complete resection rate. Nevertheless, there was also a 100% perforation rate, although all these were closed intraoperatively. There was no postoperative gastric bleeding, peritonitis sign, or abdominal abscess. No lesion residual or recurrence was found during the 6-24 month follow-up period.

Dr. Khashab is a consultant and medical advisory board member for Boston Scientific and Olympus.

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