Reply to Chun et al. (2)

We read the letter of Chun et al. with great attention. They raised several pertinent questions about endoscopic submucosal tunnel dissection (ESTD) for the treatment of upper gastrointestinal submucosal tumors (SMTs), concerning the indications, advantages, and disadvantages. We do agree with some of the opinions they put forward. However, regarding some other questions, we would like to give some further explanation.

We do agree with their opinion that “Resection of the mass should be considered in symptomatic patients, for those in whom diagnosis is uncertain, and for those in whom the lesion shows interval growth during surveillance endoscopy.” It is usually suggested that in asymptomatic patients, gastrointestinal SMTs smaller than 3 cm should be followed up by periodic endoscopy and/or endoscopic ultrasound (EUS). However, in our study, we found that some patients became stressed and anxious when they were informed that they had submucosal tumors that needed periodic surveillance endoscopy, even though the tumors were benign at present. Some other patients who received endoscopy periodically also felt burdened by the follow-up and were also worried about when the surveillance endoscopy would end. They therefore had a strong desire for the tumors to be removed, as has been found in other studies [1] [2]. This is why the patients were included for ESTD although they had no symptoms and there was no interval growth [3].

Although two patients in our study, had complications, such as pneumothorax and subcutaneous emphysema, this does not mean that ESTD is dangerous. Normal air insufflation was used, during ESTD for the two patients with complications, However, there were no complications in the four patients with CO₂ insufflation. In our experience, tunnel dissection is a very safe method with fewer or no complications if CO₂ insufflation is used, as has also been proved by other studies involving tunnel technology [4] [5]. In fact, tunnel dissection is not a very difficult skill for endoscopists to master. Any endoscopist who is proficient at ESD can perform ESTD since these two methods use similar techniques and equipment. To some extent, ESTD avoids the shortcomings of ESD and is easy to perform, as we discussed in our paper [3]. Therefore, we think that ESTD is a safe and easy method for SMTs and can be used widely if well indicated.

We also carefully read the papers cited by Chun & Choi regarding laparascopic or thoracoscopic surgery for the treatment of SMTs in the esophagus or esophagogastric junction, that showed excellent results with almost no complications [6] [7]. However, laparascopic or thoracoscopic surgery have some disadvantages compared with endoscopic tunnel dissection. First, the operating time is much longer than with tunnel dissection. In the reports by von Rahden et al. [6] and Hwang et al. [7], the laparascopic or thoracoscopic operation times were 102.95 minutes and 95 minutes, respectively. In contrast, in our study [3] and another study on tunnel dissection [1], the operation times were 48.3 min and 78.7 min respectively. Secondly, the postoperative hospital stay following the laparascopic or thoracoscopic procedures is longer than that for tunnel dissection. In the report from Xu et al. [1], the patients were given a full fluid diet on postoperative day 2 and the average hospital stay was only 3.8 days. After gaining more experience, recently with another four patients treated with ESTD we have also given a full fluid diet on postoperative day 2, in the way reported by Xu et al. At the time of writing, the postoperative hospital stay has been shortened to 2 – 3 days. However, von Rahden et al. reported an average postoperative hospital stay of 7 ± 2 days [6]. Thirdly, using the laparascopic or thoracoscopic approach, it is sometimes hard to identify a precise resection area without the assistance of a gastroscope. In the study by von Rahden et al., nine of the 13 procedures were completed by thoracoscopy or laparascopy plus endoscopy. At our hospital, we are often requested to assist thoracoscopic or laparascopic surgery with gastroscopy. This is a more complicated procedure that requires good cooperation between two departments. Finally, tunnel dissection leaves no scar on the skin, which is more welcome to patients. Based on the above points, we do not think that tunnel dissection is marginal compared with other removal methods. On the other hand, we recommend that randomized clinical trials be carried out to assess which method is superior.

However, tunnel dissection does have some disadvantages: for example, SMTs less than 5 cm under the upper esophageal sphincter, and SMTs located under fibrosis or a large diverticulum, are not suitable for tunnel dissection, as pointed out by Chun & Choi. Also, it is difficult to remove SMTs larger than 4 cm by tunnel dissection because of the limited space of the tunnel where it is hard to obtain good visualization [4]. Therefore, we think that the best indication for tunnel dissection may be submucosal tumors smaller than 4 cm, in the esophagus and cardia, and without fibrosis or diverticulum at the linear proximal side of the tumor.

• References

• 1 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 (with videos). Gastrointest Endosc 2012; 75: 195-199
• 2 Park YS, Park SW, Kim TI et al. Endoscopic enucleation of upper-GI submucosal tumors by using an insulated-tip electrosurgical knife. Gastrointest Endosc 2004; 59: 409-441
• 3 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
• 4 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
• 5 Inoue H, Minami H, Kobayashi Y et al. Peroral endoscopic myotomy (POEM) for esophageal achalasia. Endoscopy 2010; 42: 265-271
• 6 Rahden BH von, Stein HJ, Feussner H et al. Enucleation of submucosal tumors of the esophagus: minimally invasive versus open approach. Surg Endosc 2004; 18: 924-930
• 7 Hwang SH, Park DJ, Kim YH et al. Laparoscopic surgery for submucosal tumors located at the esophagogastric junction and the prepylorus. Surg Endosc 2009; 23: 1980-1987