Published online Jan 14, 2019. doi: 10.3748/wjg.v25.i2.245
Peer-review started: September 27, 2018
First decision: October 23, 2018
Revised: November 19, 2018
Accepted: December 19, 2018
Article in press: December 19, 2018
Published online: January 14, 2019
Submucosal tumors (SMTs) have a greater possibility of malignancy when they originate from the muscularis propria (MP) layer, have a large diameter, or are mesenchymal neoplasms. Without resection, it is difficult to obtain an accurate diagnosis of the subtypes of SMTs even by endoscopic ultrasound-guided fine needle aspiration and biopsy, which are regarded as the most reliable methods. Submucosal tunneling endoscopic resection (STER), which was inspired by digestive endoscopic tunnel technique, was reported for the resection of SMTs originating from the MP layer with the advantage to maintain the integrity of the mucosa in 2012. As a minimally invasive produce, STER acts an important role in the treatment of SMTs.
Few studies describing STER for SMTs located in the MP layer have enrolled large populations of greater than 100 cases. Studies enrolled large samples are needed. Although STER procedures for SMTs located in the cardia were regarded to be more challenging due to the need to create a tunnel from the esophagus, through the lower esophageal sphincter, to the cardia, no studies comparing the effectiveness and safety of STER for SMTs located in different locations have been performed.
In this retrospective study, we further evaluated the effectiveness and safety of STER for gastrointestinal (GI) SMTs originating from the MP layer in a large population and compared the feasibility of STER for resection of esophageal and cardial SMTs.
From May 2012 to November 2017, 173 consecutive patients with upper GI SMTs of the MP layer underwent STER. Overall, 165 patients were included, and 8 were excluded. The en bloc resection rate, complete resection rate, residual rate, and recurrence rate were calculated to evaluate the effectiveness of STER, and the complication rate was recorded to evaluate its safety. Effectiveness and safety outcomes of STER were compared between esophageal and cardial SMTs.
En bloc resection was achieved in 128 of the 165 lesions treated with an en bloc resection rate of 78.7%. Four SMTs were not resected completely owing to large size, deep invasion, and/or proximity to the aortic arch, leading to a residual rate of 2.4% (4/165). No recurrence was noted during follow-up. The complete resection rate was 78.7%. Thirty-five patients had intraoperative or postoperative complications, with a rate of 21.2% (35/165). The most common complications were fever (13/165), mucosal injury (12/165), and gas-related complications (10/165). No severe complications occurred. En bloc resection was achieved in 86 (81.1%) patients in the esophagus group and 42 (72.1%) in the cardia group, and there was no significant difference between them (P = 0.142). There was no significant difference in the complication rate between the two groups (esophagus, 19.8%; cardia, 23.7%; P = 0.555). The most common complications in the esophagus group were gas-related complications (8/106) and fever (9/106), while mucosal injury (9/59) was the most common complication in the cardia group. However, the accurate origin from the MP layer of the SMTs was not taken into consideration in this study and the number of patients in the cardia group was small.
STER is an effective and safe therapy for GI SMTs of the MP layer with an en bloc resection rate of 78.7% and a complication rate of 21.2%. No recurrence was observed during follow-up, even after piecemeal resection. Although STER for cardial SMTs was more challenging than that of esophageal SMTs, their en bloc resection rates were comparable even though cardial SMTs were larger and more irregular than esophageal SMTs. The most common complications in the esophagus group were gas-related complications and fever, while mucosal injury was the most common complication in the cardia group.
Although piecemeal resection may do not influence long-term outcomes, it affects pathological evaluation. Therefore, en bloc resection should be maintained. Randomized controlled studies involving a large population are warranted to evaluate the long-term outcome of STER compared with other treatments for SMTs originating from the MP layer, such as endoscopic submucosal excavation and endoscopic full-thickness resection.