Submucosal Tunneling Endoscopic Resection for Gastric Submucosal Tumors: a Comparison Between Cardia and Non-cardia Location

Endoscopic removal of gastrointestinal lesions by using third space endoscopy techniques

The concept of submucosal space, or rather the "third space", located between the intact mucosal flap and the muscularis propria layer of the gastrointestinal tract, represents a tunnel that the endoscopist could use to perform interventions in the muscularis propria layer or breech it to enter the mediastinum or the peritoneal cavity without full thickness perforation. The tunnel technique can be used both for the removal of mucosal tumours, called endoscopic submucosal tunnel dissection (ESTD), for the removal of subepithelial tumours (SELs), called submucosal tunnelling endoscopic resection (STER), and for the removal of extra-luminal lesions (for example in the mediastinum or in the rectum), called submucosal tunnelling endoscopic resection for extraluminal tumours (STER-ET). Aim of this updated narrative review, is to summarize the evidences that analyses indications, and outcomes of tunnelling techniques for the treatment of above mentioned lesions.

Present situation of minimally invasive surgical treatment for early gastric cancer

Minimally invasive surgery is a kind of surgical operation, which is performed by using professional surgical instruments and equipment to inactivate, resect, repair or reconstruct the pathological changes, deformities and wounds in human body through micro-trauma or micro-approach, in order to achieve the goal of treatment, its surgical effect is equivalent to the traditional open surgery, while avoiding the morbidity of conventional surgical wounds. In addition, it also has the advantages of less trauma, less blood loss during operation, less psychological burden and quick recovery on patients, and these minimally invasive techniques provide unique value for the examination and treatment of gastric cancer patients. Surgical minimally invasive surgical techniques have developed rapidly and offer numerous options for the treatment of early gastric cancer (EGC): endoscopic mucosal resection (EMR), underwater EMR (UEMR), endoscopic submucosal dissection (ESD), endoscopic full-thickness resection (EFTR), endoscopic submucosal excavation (ESE), submucosal tunnel endoscopic resection), laparoscopic and endoscopic cooperative surgery (LECS); Among them, EMR, EFTR and LECS technologies have a wide range of applications and different modifications have been derived from their respective surgical operations, such as band-assisted EMR (BA-EMR), conventional EMR (CEMR), over-the-scope clip-assisted EFTR, no-touch EFTR, the inverted LECS, closed LECS, and so on. These new and improved minimally invasive surgeries are more precise, specific and effective in treating different types of EGC.

Risk factors for complications and incomplete resection after endoscopic resection for duodenal submucosal tumors

BACKGROUND AND AIM

Endoscopic resection (ER) has been used to remove submucosal tumors (SMTs) in recent years; however, duodenal ER is associated with high rates of immediate or delayed bleeding and perforation. Whether ER can be recommended for the treatment of duodenal SMTs remains controversial. Therefore, we aimed to investigate the clinical outcomes associated with the ER of duodenal SMTs and to assess possible predictive factors for complications and incomplete resection.

METHODS

This retrospective study included 141 patients with duodenal SMTs. The therapeutic outcomes from ER and procedure-related complications were analyzed.

RESULTS

Of the 141 patients, 78.7% achieved complete resection and nine (6.4%) developed complications. The multivariate analysis suggested that location near the duodenal papilla (P = 0.010) and diameter exceeding 15 mm (P = 0.091) of duodenal SMTs were independent risk factors for complications in ER. Besides, submucosal fibrosis (P = 0.042), location near the duodenal papilla (P = 0.049), and irregular morphology (P = 0.067) were independent risk factors for incomplete resection.

CONCLUSIONS

ER can be recommended as an effective and minimally invasive treatment for duodenal SMTs.

Submucosal Tunneling Techniques for Tumor Resection

The concept of third space endoscopy is based on the principle that the deeper layers of the gastrointestinal tract can be accessed by tunneling in the submucosal space and maintaining the integrity of the overlying mucosa. The mucosal flap safety valve enabled endoscopists to use submucosal space securely. The era of third space endoscopy started with peroral endoscopic myotomy for treatment of achalasia and has expanded to treat various other gastrointestinal disorders, such as mucosal lesions, submucosal tumors, extraluminal tumors, and refractory gastroparesis, Zenker diverticulum, and restoration of the completely obstructed esophageal lumen. Third space endoscopy rapidly emerged as a minimally invasive alternative to conventional surgery. Many studies discovered that this technique is safe and effective with excellent outcomes. Our review focused on the indications, techniques, clinical management, and adverse events of submucosal tunneling techniques for tumor resection.

A scoring system to support surgical decision-making for cardial submucosal tumors

Background and study aims  Submucosal tunneling endoscopic resection (STER) and non-tunneling techniques are two alternative options for the treatment of cardial submucosal tumors (SMTs). We aimed to establish a regression model and develop a simple scoring system (Zhongshan Tunnel Score) to help clinicians make surgical decisions for cardial submucosal tumors. Patients and methods  A total of 246 patients who suffered cardial SMTs and received endoscopic resection were included in this study. All of them were randomized into either the training cohort (n = 147) or the internal validation cohort (n = 99). Then, the scoring system was proposed based on multivariate logistic regression analysis in the training cohort and assessed in the validation cohort. Results  Of 246 patients, 97 were treated with STER and the others with non-tunneling endoscopic resection. In the training stage, four factors were weighted with points based on the β coefficient from the regression model, including irregular morphology (-2 points), ulcer (2 points), the direction of the gastroscope (-2 points for forward direction and 1 point for reverse direction), and originating from the muscularis propria (-2 points). The patients were categorized into low-score (< -4), medium-score (-4 to -3) and high-score (> -3) groups, and those with low scores were more likely to be treated with STER. Our score model performed satisfying discriminatory power in internal validation (Area under the receiver-operator characteristic curve, 0.829; 95 % confidence interval, 0.694-0.964) and goodness-of-fit in the Hosmer-Lemeshow test ( P  = .4721). Conclusions  This scoring system could provide clinicians the references for making decisions about the treatment of cardial submucosal tumors.

Efficacy and safety of submucosal tunneling endoscopic resection for gastric submucosal tumors: a systematic review and meta-analysis

INTRODUCTION

submucosal tunneling endoscopic resection (STER) can be an effective treatment for submucosal tumors (SMTs) in the esophagus and cardia. However, STER may be more difficult to perform in the stomach than in the esophagus due to special anatomical and physiological features. The feasibility of STER to remove gastric STMs has not been systematically investigated. Therefore, this meta-analysis aimed to evaluate the safety and efficacy of STER for gastric SMTs.

MATERIAL AND METHODS

a comprehensive literature search of the Medline, Embase, PubMed, and Cochrane Library databases was conducted. Complete resection and en-bloc resection rates were considered as the primary outcome measures. The secondary outcome measure was the pooled estimate of complications.

RESULTS

nine studies including 301 patients with 305 lesions were finally included. The pooled estimate of en-bloc resections was 95.1 % (95 % CI: 88.9-97.9 %), Cochran's Q-test, p = 0.151, and the weighted pooled rate (WPR) for complete resection was 97.9 % (95 % CI: 93.6-99.3 %), Cochran's Q-test, p = 0.778. In addition, the pooled estimate of gas-related complications was 8.7 % (95 % CI: 4.6-15.9 %), Cochran's Q-test, p = 0.057. The pooled estimate for mucosal laceration was 4.2 % (95 % CI: 2.2-7.9 %), Cochran's Q-test, p = 0.572. The pooled estimate for delayed bleeding was 2.1 % (95 % CI: 0.9-4.8 %), Cochran's Q-test, p = 0.985. The pooled estimate of inflammation-related complications was 8.6 % (95 % CI: 5.2-13.9 %), Cochran's Q-test, p = 0.308.

CONCLUSION

STER is an effective and safe technique for removing gastric SMTs with low complications, and complications, when encountered, can be treated conservatively.

Current status of endoscopic submucosal tunnel dissection for treatment of superficial gastrointestinal neoplastic lesions

INTRODUCTION

With the widespread application of screening endoscopy and development of endoscopy-related instruments, more and more gastrointestinal cancers are detected in an early stage. Endoscopic resection is a preferred method for selected patients with superficial gastrointestinal neoplastic lesions, and endoscopic submucosal dissection (ESD) has become a standard method for its ability to perform en bloc resection regardless of the lesion size. ESD can be performed in a conventional or tunneling way, and the latter is termed endoscopic submucosal tunnel dissection (ESTD).

AREA COVERED

In the present review, we provided a comprehensive review on ESTD for treatment of superficial gastrointestinal neoplastic lesions. We mainly focus on technical details, safety and efficacy of ESTD for esophageal, gastric and colorectal lesions. The present review is expected to provide tips for operators who are going to perform ESTD.

EXPERT OPINION

The best indication of ESTD is large superficial esophageal neoplastic lesions (circumferential extent > 1/3 and longitudinal extent > 3 cm). Although ESTD has shown promising primary results for superficial gastric and colorectal neoplastic lesions, it is technically difficult and should be attempted only in experienced hands. Post-treatment stricture is a major concern, and preventive measures are recommended for patients with high risk of post-ESTD stricture.