Endoluminal resection and tissue acquisition

Endoscopic resection as curative treatment is feasible and indicated for gastrointestinal adenomas and early cancer limited to the mucosal layer and submucosal layers, where the risk for nodal and distant metastases is minimal. The initial technique of endoscopic resection, endoscopic mucosal resection, was limited by the inability to have en bloc resections for lesions larger than 2 cm. This meant that proper assessment of resection margins and depths was not possible in these cases, with the risk of incomplete resection and remnant lesions. In the last decade, the technique of endoscopic submucosal dissection was introduced, and this has allowed en bloc resection of superficial cancers of the esophagus, stomach, and colon. Cumulative data have shown high en bloc resection rates and excellent short-term and long-term outcomes when treatment inclusion criteria are adhered to. Endoscopic resection techniques were recently applied in the context of submucosal lesions. In the case of lesions located in the muscularis mucosa and submucosal layers, the gastrointestinal wall is not breached during endoscopic resection. However, in the case of submucosal lesion located in the muscularis propria layer, endoscopic mucosal resection or endoscopic submucosal dissection would result in perforation which may not be easily closed endoscopically. The technique of endoscopic submucosal tunneling was introduced in the context of peroral endoscopic myotomy for the treatment of achalasia. The principle was extended to the resection of tumors arising from the muscularis propria layer, with promising results.