Reply to Chun et al. (1)

I appreciate the interest of Chun et al. in these articles. Our article [1] and that of Gong et al. [2] reported excision of submucosal tumors using a submucosal endoscopic approach. The technical feasibility and clinical safety of submucosal endoscopy have already been established and reported in the treatment of achalasia (peroral endoscopic myotomy [POEM]) [3] [4] [5]. The removal of submucosal tumors originating from the proper muscle layer was developed as an extended application of submucosal endoscopy [1] [2]. The same technique has also been reported by Xu et al. [6]. These reports on the submucosal endoscopic approach for submucosal tumors [1] [2] [6] are not comparative studies that make comparisons with the direct approach method [7], and thus we do not conclude which method is superior to the other. Both techniques actually have advantages and disadvantages.

The major advantage of submucosal endoscopy is the substantial preservation of the mucosal layer which is expected to work as a robust barrier against exposure of the mediastinum to intraluminal content even when the muscle layer has a large defect. Leiomyomas are often derived from the inner circular muscle layer. When a submucosal tumor is directly excised together with the overlying mucosa, the remaining outer longitudinal layer becomes the only barrier to the mediastinum. But before the procedure, nobody predicts that the outer longitudinal muscle layer will remain intact. Particularly when the intention is to resect a large tumor using the directly approach technique, a full defect of the esophageal wall may happen and it is often difficult to close it perfectly. It may subsequently cause severe inflammation. In this situation the most effective treatment will be to both keep the patient fasting and to inject antibiotics. We also have clinical experience of the direct approach method in eight cases (not published). Our indication is a submucosal tumor more than 2 cm in size (2.5 – 8 cm). In this series prolonged inflammation has occurred, and extension of the fasting period until local inflammation has ceased has been mandatory. Eventually all the patients were satisfactory without additional treatment. When we allow an extended fasting period in these patients, the direct approach method to submucosal tumors larger than 2 cm is very acceptable. In other words, the excellent clinical results of endoscopic submucosal dissection (ESD) and POEM tell us that nothing untoward happens as long as one layer of either the mucosa or the muscle is kept intact, but if we lose both layers then this has to be carefully followed up post procedure.

As indicated by Chun & Choi, location of submucosal tumors close to the upper esophageal sphincter may be a poor indication for the submucosal endoscopic approach, but tumor location in the middle or lower esophagus or the gastric cardia is a good indication for a submucosal endoscopic approach for tumors smaller than 4 cm. On the other hand, the direct incision method may have the advantage that it can be used to access any part of the esophagus and cardia. As Chun & Choi mention, the indications for resection for submucosal tumors less than 2 cm in size is another topic for discussion. We do not perform excision for esophageal leiomyomas less than 2 cm in size.

At the moment recent clinical research confirms that two endoscopic approaches, the direct approach and the submucosal approach, can be selected to excise submucosal tumors, and the actual application of these two methods will be clarified in the near future.

• References

• 1 Inoue H, Ikeda H, Hosoya T et al. Submucosal endoscopic tumor resection for subepithelial tumors in the esophagus and cardia. Endoscopy 2012; 44: 225-230
• 2 Gong W, Xiong Y, Zhi F et al. Preliminary experience of endoscopic submucosal tunnel dissection for upper gastrointestinal submucosal tumors. Endoscopy 2012; 44: 231-235
• 3 Inoue H, Minami H, Kobayashi Y et al. Peroral endoscopic myotomy (POEM) for esophageal achalasia. Endoscopy 2010; 42: 265-271
• 4 Swanstrom LL, Rieder E, Dunst CM. A stepwise approach and early clinical experience in peroral endoscopic myotomy for the treatment of achalasia and esophageal motility disorders. J Am Coll Surg 2011; 213: 751-756
• 5 von Renteln D, Inoue H, Minami H et al. Peroral endoscopic myotomy for the treatment of achalasia: a prospective single center study. Am J Gastroenterol 2012; 107: 411-417
• 6 Xu MD, Cai MY, Zhou PH et al. Submucosal tunneling endoscopic resection: a new technique for treating upper GI submucosal tumors originating from the muscularis propria layer. Gastrointest Endosc 2012; 75: 195-199
• 7 Hyun JH, Jeen YT, Chun HJ et al. Endoscopic resection of submucosal tumor of the esophagus: results in 62 patients. Endoscopy 1997; 29: 165-170