Endolumenal endoscopic full-thickness resection of muscularis propria-originating gastric submucosal tumors

Current Status of Endoscopic Full-Thickness Resection for Gastric Subepithelial Tumors: A Literature Review Over Two Decades

BACKGROUND

With the development of endoscopic technology and devices, endoscopic full-thickness resection (EFTR) has been challengingly introduced for gastric subepithelial tumors (SETs). The resection and closure strategies are under investigation. This systematic review was performed to assess the current status and limitations of EFTR for gastric SETs.

SUMMARY

MEDLINE was searched using the keywords "endoscopic full-thickness resection" or "gastric endoscopic full-thickness closure" AND "gastric" or "stomach" from January 2001 to July 2022. The outcome variables were the complete resection rate, major adverse event (AE) rate including delayed bleeding and delayed perforation, and closure-associated outcomes. Among 288 studies, 27 eligible studies involving 1,234 patients were included in this review. The complete resection rate was 99.7% (1,231/1,234). The major AE rate was 1.13% (14/1,234), with delayed bleeding in two (0.16%) patients, delayed perforation in one (0.08%), panperitonitis or abdominal abscess in three (0.24%), and other AEs in eight (0.64%). Surgical interventions were required intraoperatively or postoperatively in 7 patients (0.56%). Three patients underwent intraoperative conversion to surgery, due to intraoperative massive bleeding, technical difficulty of closure, and retrieval of falling tumor in the peritoneal cavity. Postoperative surgical rescues for AEs were required in four (0.32%). Subgroup analysis of AE outcomes showed no significant differences among closure techniques consisting of endoclips, purse-string suturing, and over-the-scope clips.

KEY MESSAGES

This systematic review demonstrated acceptable outcomes of EFTR and closure for gastric SETs, indicating that EFTR is a promising forthcoming procedure.

Endoscopic full-thickness resection, indication, methods and perspectives

Minimally invasive surgery has emerged as the dominant theme of modern surgery, in which endoscopic surgery plays a key role. The technique of endoscopic surgery has evolved continuously with extensive research, improving the treatment modalities as well as expanding the indications for its use. As an active perforation endoscopic technique, endoscopic full-thickness resection (EFTR) is mainly used in the treatment of submucosal tumors (SMTs) of the gastrointestinal tract. With decades of evolution, EFTR has gradually developed into a mature endoscopic operation. Based on clinical experience and current research, indications, techniques, clinical outcomes and future perspectives for EFTR are discussed in this paper. We performed a bibliometric study on EFTR literature and showed robust data through a brief meta-analysis on the topic.

Endoscopic Full Thickness Resection: A Systematic Review

Background Endoscopic full thickness resection (EFTR) is an emerging therapeutic option for resecting subepithelial lesions (SELs) and epithelial neoplasms. We aimed to systematically review the techniques, applications, outcomes, and complications of EFTR.

Methods A systematic literature search was performed using PubMed. All relevant original research articles involving EFTR were included for the review along with case report/series describing novel/rare techniques from 2001 to February 2022.

Results After screening 7,739 citations, finally 141 references were included. Non-exposed EFTR has lower probability of peritoneal contamination or tumor seeding compared with exposed EFTR. Among exposed EFTR, tunneled variety is associated with lower risk of peritoneal seeding or contamination compared with non-tunneled approach. Closure techniques involve though the scope (TTS) clips, loop and clips, over the scope clips (OTSC), full thickness resection device (FTRD), and endoscopic suturing/plicating/stapling devices. The indications of EFTR range from esophagus to rectum and include SELs arising from muscularis propria (MP), non-lifting adenoma, recurrent adenoma, and even early gastric cancer (EGC) or superficial colorectal carcinoma. Other indications include difficult locations (involving appendicular orifice or diverticulum) and full thickness biopsy for motility disorders. The main limitation of FTRD is feasibility in smaller lesions (<20–25 mm), which can be circumvented by hybrid EFTR techniques. Oncologic resection with lymphadencetomy for superficial GI malignancy can be accomplished by hybrid natural orifice transluminal endoscopic surgery (NOTES) combining EFTR and NOTES. Bleeding, perforation, appendicitis, enterocolonic fistula, FTRD malfunction, peritoneal tumor seeding, and contamination are among various adverse events. Post OTSC artifacts need to be differentiated from recurrent/residual lesions to avoid re-FTRD/surgery.

Conclusion EFTR is safe and effective therapeutic option for SELs, recurrent and non-lifting adenomas, tumors in difficult locations and selected cases of superficial GI carcinoma.

Exposed endoscopic full-thickness resection without laparoscopic assistance for gastric submucosal tumors: A systematic review and pooled analysis

BACKGROUND

Exposed endoscopic full-thickness resection (Eo-EFTR) is emerging as a promising minimally invasive alternative to surgery for the treatment of deep gastric submucosal tumors (G-SMTs). However, literature concerning this subject is heterogeneous and data mostly come from relatively small retrospective studies.

AIMS

We aimed to perform a pooled analysis of published data with regard to gastric Eo-EFTR, providing a pooled estimate of technical and clinical outcomes.

METHODS

The protocol was registered in PROSPERO. MEDLINE and EMBASE databases were searched for studies published from 1998 to 2020. The primary outcomes were complete resection and surgical conversion rates. The secondary outcomes were overall and selected major adverse events rates. The Forest plots on primary and secondary endpoints were produced based on fixed and random effect models.

RESULTS

Nineteen studies including 952 Eo-EFTR-treated G-SMTs were included. The pooled estimate of the complete resection rate and surgical conversion rates was 99.3% and 0.09%, respectively. The pooled estimate of overall major adverse events, delayed bleeding, delayed perforation and peritonitis, abdominal abscess and/or abdominal infection was 0.29%, 0.14%, 0.14%, and 0.12%, respectively.

CONCLUSION

Gastric Eo-EFTR has a high rate of complete resection with a low surgical conversion rate. It appears to be relatively safe and might represent a non-inferior minimally invasive alternative to surgery in selected cases.

Advances in endoscopic resection: a review of endoscopic submucosal dissection (ESD), endoscopic full thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER)

Subepithelial lesions are often detected incidentally in patients undergoing an endoscopy. They are common tumors of the gastrointestinal (GI) tract which can originate from different layers of the GI tract wall. These lesions can be further classified based on GI layer of origin and unique histochemical staining. While most are benign and asymptomatic, some of these lesions have malignant potential with distant metastases. However, current diagnostic modalities including endoscopy with biopsy or endoscopic ultrasound with fine needle aspiration are not always reliable. In addition, management of these lesions has historically involved surgical resection via open or laparoscopic approaches. In recent years, with advancement in endoscopic techniques and improvement in endoscopists' skills, less invasive procedures such as endoscopic submucosal dissection (ESD), endoscopic full thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER) have been developed and now are being used by endoscopists worldwide. Upon reviewing the literature, multiple studies have shown the advantages of these endoscopic techniques when compared with surgical treatment. As a result, there has been a dramatic shift towards minimally invasive endoscopic procedures for the management of these subepithelial lesions. In this review article, we will discuss these endoscopic resection techniques in detail, their safety and efficacy, as well as comparison studies to other therapeutic modalities.

The necessarity of treatment for small gastric subepithelial tumors (1-2 cm) originating from muscularis propria: an analysis of 972 tumors

Background and objectives

Up till now, there are still controversies about the specific indication of endoscopic resection for small gastric subepithelial tumors (gSETs) originating from muscularis propria. We aimed to investigate the safety of endoscopic resection and postoperative pathology analysis.

Method

The patients with primary small gSETs originating from muscularis propria, treated by endoscopic resection in the endoscopic center of Shengjing Hospital between January, 2011 and September, 2019 were enrolled. The complete resection rate, adverse events and clinicopathological features were recorded.

Result

A total of 936 patients with 972 gastric SETs ≤ 2 cm originating from muscularis propria were included in our study. All the lesions were successfully treated by endoscopic resection. Nearly half of lesions were proved to be gastrointestinal stromal tumor (GIST) [n = 411 (42.3%)] according to postoperative pathology. All the objects were further subdivided into 2 groups, ≤ 1 cm, > 1 and ≤ 2 cm gSETs. The risk of gastric GIST of intermediate/high risk in the group (> 1 and ≤ 2 cm gSETs) is 8.41 times as that of gastric GIST in the group (the size of gastric ≤ 1 cm gSETs) (P < 0.05).

Conclusion

Endoscopic resection is a safe and effective treatment for small gSETs. gSETs (1–2 cm) is more risky than gSETs (≤ 1 cm) and should be resected. This should be evaluated by further studies.

Endoscopic Resection of Gastrointestinal Stromal Tumor: Is It Safe?

Recently, results from clinical studies of endoscopic resection of gastrointestinal stromal tumor (GIST) in the stomach are being reported. This procedure has several advantages, such as the provision of a definite diagnosis and therapeutic plan, avoidance of frequent follow-up examination, and reduction of patients’ anxiety. However, several concerns also exist such as a limited number of studies, low R0 resection rate, and relatively shorter follow-up period compared with surgical resection. Nevertheless, it is encouraging that most of the post-procedural complications have been treated with conservative management and that some of the patients did not show recurrence of the tumor during long-term follow-up. The selection of suitable cases and the experience of the endoscopists are the most important factors for successful endoscopic resection of gastric GIST. Development of novel procedures as well as collaboration with laparoscopic surgeons are currently in progress.

Closure techniques in exposed endoscopic full-thickness resection: Overview and future perspectives in the endoscopic suturing era

Exposed endoscopic full-thickness resection (EFTR) without laparoscopic assistance is a minimally invasive natural orifice transluminal endoscopic surgery technique that is emerging as a promising effective and safe alternative to surgery for the treatment of muscularis propria-originating gastric submucosal tumors. To date, various techniques have been used for the closure of the transmural post-EFTR defect, mainly consisting in clip- and endoloop-assisted closure methods. However, the recent advent of dedicated tools capable of providing full-thickness defect suture could further improve the efficacy and safety of the exposed EFTR procedure. The aim of our review was to evaluate the efficacy and safety of the different closure methods adopted in gastric-exposed EFTR without laparoscopic assistance, also considering the recent advent of flexible endoscopic suturing.

Novel endoscopic management for small gastric submucosal tumors: A single-center experience (with video)

BACKGROUND AND AIMS

To explore the novel treatment of small gastric submucosal tumors (SMTs) originating from the muscularis propria layer (SMT-MPs), we utilized endoscopic band ligation (EBL) with a precut of the covering mucosa.

METHODS

From Jan. 2012 to Dec. 2019, 111 patients with 124 gastric SMT-MPs were treated by precutting EBL. The clinical characteristics, operation duration, postoperative adverse events, and follow-up profiles were retrospectively collected.

RESULTS

A total of 124 tumors from 111 patients were successfully treated by precutting EBL. No adverse events, including perforation and major bleeding, were observed. Furthermore, 93 patients (83.8%) underwent endoscopic surveillance postoperatively, and during the follow-up period, no local recurrence was detected.

CONCLUSIONS

Precutting EBL appears to be a safe and simple method for removing gastric SMT-MPs < 16 mm (mainly indicated for potentially malignant GISTs), but further studies with longer follow-up are needed to assess the radicality of this intervention.

A Review of Endoscopic Full-thickness Resection, Submucosal Tunneling Endoscopic Resection, and Endoscopic Submucosal Dissection for Resection of Subepithelial Lesions

Gastrointestinal subepithelial tumors (SETs) are often found while performing routine endoscopy. Recently, there has been the development of new endoscopic techniques such as endoscopic submucosal dissection, submucosal tunnel endoscopic resection, and endoscopic full-thickness resection, all minimally invasive approaches which have made it possible to resect SETs that were previously resected with surgery. This review discusses the endoscopic treatment of patients with SETs, outcomes for endoscopic treatment, procedure-related complications, and advantages and disadvantages of these endoscopic techniques.

Retrospective Comparison of Endoscopic Full-Thickness Versus Laparoscopic or Surgical Resection of Small (≤ 5 cm) Gastric Gastrointestinal Stromal Tumors

AIM AND BACKGROUND

The aim of this study was to compare the efficacy and safety between endoscopic full-thickness resection (EFR) and laparoscopic or surgical resection methods for gastric gastrointestinal stromal tumor (GIST) in size of 5.0 cm or less. Gastric GISTs are common, and resection is the most effective treatment.

METHOD

We retrospectively reviewed 216 resections of gastric GISTs in size of up to 5.0 cm at our center from 2009 to 2017.Eligible resection cases were divided into EFR (n = 85), laparoscopic(n = 64), and surgical (n = 67) groups. The clinical records, patient demographic, symptoms, perioperative data, pathological findings, and long-term follow-up outcomes were collected and compared statistically.

RESULTS

No tumor rupture or recurrence occurred in the three groups. The prevalence of complications was significantly lower in EFR (5.9%) than both laparoscopic (7.8%) and surgical group (16.4%) (P < 0.01). In EFR group, the R0 resection rate (95.3%) was significantly lower than in the laparoscopic group and surgical group (100%) (P < 0.001). The hospital cost (OR = 62.79, CI: 12.954-304.363, P < 0.0001) were significantly lower in the EFR than in the laparoscopic group. The hospital cost (OR = 39.032, CI: 8.045-189.371, P < 0.0001) and post-operative diet time (OR = 2.779, CI: 1.225-6.304, P < 0.05) were also significantly lower in the EFR than in the surgical group.

CONCLUSION

EFR was a feasible treatment for gastric GISTs of size of ≤ 5.0 cm with an acceptable complete resection rate. In addition, EFR had significantly fewer postoperative complications, shorter length of hospital stay, and lower cost.

Efficacy and safety of gastric exposed endoscopic full-thickness resection without laparoscopic assistance: a systematic review

Background and study aims  Exposed endoscopic full-thickness resection (Eo-EFTR) without laparoscopic assistance is a minimally invasive natural orifice transluminal endoscopic surgery (NOTES) technique that has shown promising efficacy and safety in resection of gastric submucosal tumors (G-SMTs) arising from muscularis propria (MP). However, data on the efficacy and safety of gastric Eo-EFTR mostly come from relatively small retrospective studies and concern regarding its use still exists. The aim of our systematic review was to assess the efficacy and safety of gastric Eo-EFTR without laparoscopic assistance. Methods  A detailed MEDLINE and EMBASE search was performed for papers published from January 1998 to November 2019 and reporting on gastric Eo-EFTR without laparoscopic assistance. The search strategy used the terms "endoscopic full thickness resection" and "gastric" or "stomach". The primary outcomes were complete resection and surgical conversion rates. The secondary outcomes were overall major adverse events, delayed bleeding, delayed perforation, peritonitis, abdominal abscess and/or abdominal infection and successful Eo-EFTR. Results  Fifteen Asian studies were included in our final review, providing data on 750 Eo-EFTR-treated G-SMTs. The per-lesion rate of complete resection and surgical conversion were 98.8 %\0.8 %, respectively. The per-lesion rate of major adverse events, delayed bleeding, delayed perforation and peritonitis, abdominal abscess and/or abdominal infection was 1.6 %\0.5 %\0.1 %\0.9 %, respectively. The per-lesion rate of successful Eo-EFTR (i. e. complete tumor resection and effective endoscopic defect closure) was 98.3 %. Conclusions  Eo-EFTR without laparoscopic assistance appears to be highly effective and safe NOTES for removing deep G-SMTs, particularly those arising from MP layer.

Endoscopic Full-Thickness Resection for Gastric Subepithelial Lesions Arising from the Muscularis Propria

Most cases of gastric subepithelial lesions follow a good clinical course; however, some lesions progress to malignant tumors, and treatment of tumors with a high risk of malignancy is essential. Surgical excision has been the primary treatment for tumors originating from the propria muscle layer, but it has the disadvantages of being invasive and causing postoperative functional abnormalities. With the development of endoscopic techniques and instruments, the role of endoscopic resection, which is a less invasive method for the removal of gastric subepithelial lesions, has been attracting attention. We performed an endoscopic full-thickness resection for 8 patients with gastric subepithelial lesions originating from the muscularis propria. No fatal complications occurred. Our findings suggest the need to develop various devices for resection and closure and to accumulate further experience through additional studies to prevent complications and specimen loss.

Optimal Endoscopic Resection Technique for Selected Gastric GISTs. The Endoscopic Suturing System Combined with ESD-a New Alternative?

Background and Study Aim: In terms of therapeutic management, gastrointestinal stromal tumors (GISTs) seem to be the most difficult group of subepithelial gastrointestinal lesions (SELs). Despite various treatment option, choice of optimal management remains a dilemma in daily practice. Our aim was to evaluate a new hybrid resection technique of gastric GISTs type III as a modality of endoscopic full-thickness resection. Methods: Three males and one female (mean age of 68) were qualified for the procedure. Endoscopic full-thickness resections consisted of the endoscopic resection combined with suturing by Apollo OverStitch System. The main inclusion criterium was a complete diagnosis of GISTs (computed tomography (CT), endoscopic ultrasound (EUS), fine-needle biopsy (FNB)) with the evaluation of the tumor features, especially, the location in the gastric wall. All of the tumors were type III with a diameter between 20–40 mm. The lesions were located in the corpus (1), antrum (1) and between gastric body and fundus (2). All procedures were performed in 2019. Results: The technical and therapeutic success rate was 100% and the mean resection time 107.5 min. Neither intra- nor postprocedural complications were observed. In all four cases, R0 resection was achieved. Histopathologic assessment confirmed GIST with <5mitose/50HPF in all of the tumors, with very low risk. Conclusion: Based on our outcomes, endoscopic resection combined with the sewing by Apollo OverStitch of gastric GISTs type III, with the diameter between 20–40 mm, seems to be an effective therapeutic option with a good safety profile, however further studies with a larger treatment group are needed.

Resection of the gastric submucosal tumor (G-SMT) originating from the muscularis propria layer: comparison of efficacy, patients' tolerability, and clinical outcomes between endoscopic full-thickness resection and surgical resection

Background and aims

Endoscopic full-thickness resection (EFTR) has been increasingly applied in the treatment of gastric submucosal tumors (G-SMTs) with explorative intention. This study aimed to compare the efficacy, tolerability, and clinical outcomes of EFTR and surgical intervention for the management of muscularis propria (MP)-derived G-SMTs.

Methods

Between September 2011 and May 2019, the clinical records of patients with MP-derived G-SMTs undergoing EFTR at our endoscopic unit were collected. A cohort of people with primary MP-derived G-SMTs treated by surgery was matched in a 1:1 ratio to EFTR group with regard to patients’ baseline characteristics, clinicopathologic features of the tumor and the procedure date. The perioperative outcomes and follow-up data were analyzed.

Results

In total, 62 and 62 patients were enrolled into the surgery and EFTR group, respectively, with median follow-up of 786 days. The size of G-SMTs (with ulceration) ranged from 10 to 90 mm. For patients with tumor smaller than 30 mm, surgery and EFTR group presented comparable procedural success rate (both were 100%), en bloc resection rate (100% vs. 94.7%), tumor capsule rupture rate (0% vs. 5.3%), and pathological R0 resection rate (both were 100%). EFTR had a statistically significant advantage over surgery for estimated blood loss (3.12 ± 5.20 vs. 46.97 ± 60.73 ml, p ≤ 0.001), discrepancy between the pre- and postprocedural hemoglobin level (5.18 ± 5.43 vs. 9.84 ± 8.25 g/L, p = 0.005), bowel function restoration [1 (0–5) vs. 3 (1–5) days, p ≤ 0.001], and hospital cost (28,617.09 ± 6720.78 vs. 33,963.10 ± 13,454.52 Yuan, p = 0.033). The patients with tumor larger than 30 mm showed roughly the same outcomes after comparison analysis of the two groups. However, the clinical data revealed lower en bloc resection rate (75.0% vs. 100%, p = 0.022) and higher tumor capsule rupture rate (25.0% vs. 0%, p = 0.022) for EFTR when compared to surgery. The procedure time, duration of postprocedural fasting and antibiotics usage, and hospital stay of the two groups were equivalent. The occurrence rate of adverse events within postoperative day 7 were 74.2% and 72.6% after EFTR and surgery, respectively (p = 1.000). No complications occurred during the follow-up.

Conclusion

For treatment of MP-derived G-SMTs (with or without ulceration), our study showed the feasibility and safety of EFTR, which also provided better results in terms of procedural blood loss, the postoperative bowel function restoration and cost-effectiveness when compared to surgery, whereas the surgery was superior in en bloc resection rate for G-SMTs larger than 30 mm. The postprocedural clinical outcomes seemed to be equivalent in these two resection methods.

Laparoscopic and Endoscopic Cooperative Dissection for Small Gastric Gastrointestinal Stromal Tumor without Causing Injury to the Mucosa

Objective

To investigate the feasibility of laparoscopic and endoscopic cooperative dissection (LECD) for small gastric gastrointestinal stromal tumors (GISTs) without causing injury to the mucosa, compared with ESD surgery which is widely used now.

Methods

A total of 25 patients with small gastric GISTs who underwent LECD and 20 patients with small gastric GISTs who underwent ESD between October 2014 and June 2016 were included in this study. All patients underwent curative resection for pathologically diagnosed small gastric GISTs. Patients' clinical data were retrospectively analyzed.

Results

In LECD group, the operation was successfully performed in all patients. However, in the ESD group, three patients were transferred to laparoscopic surgery due to intraoperative massive bleeding or intraoperative perforation. No additional targeted chemotherapy drugs for interstitial tumors were prescribed in two groups. There was no difference in the complete tumor capsule rate (100% vs. 90%, p = 0.11), operation time (80.76 ± 13.86 ml vs. 84.05 ± 15.33 ml, p = 0.45), major intraoperative bleeding (0 vs. 5%, p = 0.26), postoperative bleeding (0 vs. 10%, p = 0.11), and postoperative infection (0 vs. 10%, p = 0.11) between the two groups. Compared to ESD (endoscopic submucosal dissection), LECS patients had shorter postoperative indwelling gastric tube (1.04 ± 0.98 d vs. 2.85 ± 0.24 d, p < 0.01), earlier postoperative eating (1.96 ± 0.98 d vs. 3.50 ± 1.15 d, p < 0.01), shorter average postoperative hospital stay (3.44 ± 1.00 d vs. 7.85 ± 1.18 d, p < 0.01), smaller perforation rate (0 vs. 25%, p < 0.05), and fewer surgical supplies. No recurrence or metastasis cases were found between the two groups during the follow-up period, and there were no cases of death due to gastric GISTs.

Conclusion

LECD is a novel surgery for small gastric gastrointestinal stromal tumors that leads to satisfactory short-term outcomes and meets the idea of minimally invasive surgery and rapid recovery; compared with ESD, LECD surgery has some advantages in clinical practice. However, further follow-up is needed to confirm.

Comparison between laparoscopic and endoscopic resections for gastric submucosal tumors

BACKGROUND/AIMS

Open resection/laparoscopic resection (LR) is the traditional treatment of gastric submucosal tumor (G-SMT). The endoscopic resection (ER) technology provides good results for G-SMT treatment but lacks sufficient evidence-based evidence. This retrospective study aimed to compare the clinical efficacy of ER [endoscopic submucosal dissection (ESD), endoscopic submucosal excavation (ESE), and endoscopic full-thickness resection (EFR)] and LR [laparoscopic wedge resection (LWR) and laparoscopic subtotal gastrectomy (LSG)] for G-SMT.

PATIENTS AND METHODS

From January 2013 to January 2017, data of patients with G-SMT with tumor diameter <5 cm were collected from the database of The Affiliated Hospital of Qingdao University and classified based on surgical methods. Demographics, tumor characteristics, surgical outcomes, complications and tumor recurrence were recorded and compared.

RESULTS

Overall, 275 patients with G-SMT were enrolled: 152 underwent ER (ESD, n = 65; ESE, n = 23; EFR, n = 61) and 123 underwent LR (LWR, n = 93; LSG, n = 30). Age, sex, R0 resection rate, tumor location, type, recurrence and complications were not statistically significant (P > 0.05). The ER group had a significantly higher percentage of intraluminal tumor (94.1% vs 62.4%) and smaller tumor size (1.8 ± 0.8 vs 3.4 ± 1.2 cm) than the LR group. The ER group had less muscular tumors than the LR group (54.6% vs 70.7%). The ER group had no serosal tumor. The ER group had shorter hospitalization time, postoperative hospital stay and diet recovery time. The LR group had shorter operation time, less cost and less blood loss.

CONCLUSION

ER and LR are safe and effective treatments for SMT. For small intraluminally growing SMT, ER is better than LR.

Endoscopic full thickness resection versus submucosal tunneling endoscopic resection for removal of submucosal tumors: a review article

Submucosal tumors (SMT) are protuberant lesions with intact mucosa that have a wide differential. These lesions may be removed by standard polypectomy, endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), or surgically. However, in lesions that arise from the muscularis propria, full thickness resection is recommended. This can be completed using either endoscopic full thickness resection (EFTR) or submucosal tunneling endoscopic resection (STER). EFTR can be accomplished by completing a full thickness resection followed by defect closure or by securing gastrointestinal wall patency before resection. STER is an option that first creates a mucosal dissection proximal to the lesion to allow a submucosal tunnel to be created. Using this tunnel, the lesion may be resected. When comparing STER to EFTR, there was no significant difference when evaluating tumor size, operation time, rate of complications, or en bloc resection rate. However, suture time, amount of clips used, and overall hospital stay were decreased in STER. With these differences, EFTR may be more efficacious in certain parts of the gastrointestinal tract where a submucosal tunnel is harder to accomplish.

Endoscopic resection for subepithelial lesions-pure endoscopic full-thickness resection and submucosal tunneling endoscopic resection

Endoscopic full-thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER) are the frontier of therapeutic endoscopic. These two methods rely on the skillset and equipment of endoscopic submucosal dissection (ESD) while going beyond the boundaries of the gastrointestinal lumen. They are both representatives of natural orifice transluminal endoscopic surgery, with STER being a direct off-shoot of peroral endoscopic myotomy (POEM). Both techniques are designed for the removal of gastrointestinal tumors originating from the muscularis propria but tend to be used in different organs and come with respective challenges. In this review we will go over the history, indication, technique and literature of these two techniques.

Current Status of Endoscopic Resection of Gastric Subepithelial Tumors

Most gastrointestinal (GI) subepithelial tumors (SETs) are identified incidentally during endoscopic examination and are located in the stomach. Some SETs are malignant or have the potential to become malignant. Tumors originating from deeper layers, such as the muscularis propria or serosa, are not easy to diagnose and resect. Current guidelines recommend yearly endoscopic surveillance of SETs smaller than 2 cm. This recommendation may not be cost-effective in managing GI SETs. Endoscopic resection results not only in obtaining sufficient tissue for pathological diagnosis but also in resection and curing the tumor. Many different endoscopic methods for resection of GI SETs have been published in the literature. To avoid confusion, we have divided these methods into standard endoscopic submucosal dissection, modified endoscopic submucosal dissection, submucosal tunneling endoscopic resection, and nonexposed and exposed endoscopic full-thickness resection. These procedures offer less invasive approaches than surgery for resection of GI SETs and may be the most cost-effective in taking care of patients with GI SETs.

Endoscopic full-thickness resection for gastric gastrointestinal stromal tumor originating from the muscularis propria

SUMMARY OBJECTIVE: This study retrospectively reviewed 46 cases of gastric gastrointestinal stromal tumors treated by endoluminal endoscopic full-thickness resection (EFR) microsurgery in our gastrointestinal endoscopy center. We aimed to evaluate the EFR for the treatment of gastric gastrointestinal stromal tumors originating from the muscularis propria. METHODS: A total of 46 patients with gastric gastrointestinal stromal tumors originated from the muscularis propria layer from January 2012 to June 2015 were treated with EFR. The patients were followed up with gastroscope and computed tomography (CT) for evaluation of therapeutic effect and safety. RESULTS: EFR was successfully accomplished to remove all tumors in 46 patients. The mean procedure time was 82.5±39.8min (56-188min). Except in 3 leiomyomas, pathological examination confirmed gastrointestinal stromal tumor (GIST) in 43 cases. None of the patients had occurred bleeding, peritonitis and other complications after EFR. Thereafter, all patients were followed up with gastro-scope after 1, 6,12 months. CONCLUSIONS: EFR is effective and safe for patients with gastric gastrointestinal stromal tumors originated from muscularis propria layer and has the advantage of less invasive treatment and higher tumor resection rate. It should be considered for further application.

Clinical Overview of GIST and Its Latest Management by Endoscopic Resection in Upper GI: A Literature Review

Aims

To review the clinical presentation, diagnosis, assessment of risk of malignancy, and recent advances in management (mainly focusing on the role of endoscopic resection) of gastrointestinal stromal tumors (GISTs) in upper GI.

Method

We searched Embase, Web of science, and PubMed databases from 1993 to 2018 by using the following keywords: “gastrointestinal stromal tumors,” “GIST,” “treatment,” and “diagnosis.” Additional papers were searched manually from references of the related articles.

Findings

The improvement of endoscopic techniques in treating upper gastrointestinal subepithelial tumors especially gastrointestinal tumors has reduced the need for invasive surgery in patients unfit for surgery. Many studies have concluded that modified endoscopic treatments are effective and safe. These treatments permit minimal tissue resection, better dissection control, and high rates of en bloc resection with an acceptable rate of complications.

Endoscopic Full-thickness Resection for Gastric Subepithelial Tumors Originating From the Muscularis Propria: A 69-Case Series

OBJECTIVE

This report describes a mini-invasive technique called endoscopic full-thickness resection (EFR) for the treatment of gastric subepithelial tumors (SETs) originating from the muscularis propria (MP).

MATERIALS AND METHODS

We retrospectively analyzed 69 patients with gastric SETs originating from the MP at our hospital between September 2009 and July 2016. The data from each patient were reviewed, including patient information, tumor characteristics, procedure-related data, and recurrence rates.

RESULTS

Successful complete resection by EFR was achieved in 69 cases. The complete resection rate was 100%, and the mean resected tumor size was 2.25±1.40 (range, 0.6 to 6) cm. No residual tumor recurrence was detected during the follow-up period in 57 patients. The other 12 patients were lost to follow-up.

CONCLUSIONS

EFR seems to be a safe and effective technique for the treatment of patients with gastric SETs originating from the MP.

Endoscopic full-thickness resection for gastrointestinal submucosal tumors

Endoscopic full-thickness resection (EFTR) is a "changing-concept" endoscopic resection technique, which safely allows resecting deep submucosal tumors (SMTs) in the gastrointestinal (GI) wall. It's a highly promising endoscopic procedure that allows full-thickness excision of a small piece of the complete GI wall by using only a flexible endoscope. EFTR is a meeting point between surgery and endoscopy and probably the onset of many prospective combined minimally invasive therapeutic techniques that science will explore. In this review, use of the EFTR technique for gastrointestinal SMTs is highlighted, focusing on some technical aspects, indications, contraindications and outcomes.

Evolving role of the endoscopist in management of gastrointestinal neuroendocrine tumors

Neuroendocrine tumors (NETs) are uncommon gastrointestinal neoplasms but have been increasingly recognized over the past few decades. Luminal NETs originate from the submucosa of the gastrointestinal tract and careful endoscopic exam is a key for accurate diagnosis. Despite their reputation as indolent tumors with a good prognosis, some NETs may have aggressive features with associated poor long-term survival. Management of NETs requires full understanding of tumor size, depth of invasion, local lymphadenopathy status, and location within the gastrointestinal tract. Staging with endoscopic ultrasound or cross-sectional imaging is important for determining whether endoscopic treatment is feasible. In general, small superficial NETs can be managed by endoscopic mucosal resection and endoscopic submucosal dissection (ESD). In contrast, NETs larger than 2 cm are almost universally treated with surgical resection with lymphadenectomy. For those tumors between 11-20 mm in size, careful evaluation can identify which NETs may be managed with endoscopic resection. The increasing adoption of ESD may improve the results of endoscopic resection for luminal NETs. However, enthusiasm for endoscopic resection must be tempered with respect for the more definitive curative results afforded by surgical treatment with more advanced lesions.

A modified endoscopic method for resection of gastric submucosal tumor

BACKGROUND AND OBJECTIVE

Endoscopic mucosa-sparing lateral dissection (EMSLD) was developed by our group, and is used to remove gastric submucosal tumor (SMT). This study aims to evaluate the feasibility and safety of this method.

METHODS

This retrospective study included 25 patients who underwent EMSLDs at an endoscopy center as a national key unit in china from October 2015 to July 2016. The main data collected were the size of the gastric SMT, its location and origin, en bloc resection rate, operating time, intraoperative and postoperative complications, hospitalization expense, hospital days, and follow-up after hospital discharge.

RESULTS

The mean (SD) size of the gastric SMTs was 18.3 (5.9) mm; 96% (24/25) of the tumors originated in the muscularis propria; and 64% (16/25) and 28% (7/25) were located in the gastric fundus and gastric body, respectively. The rate of en bloc resection was 96% (24/25), and the rate of intraoperative perforations due to endoscopic full-thickness resection was 48% (12/25). All wounds and perforations were effectively closed using endoscopic clips combined with the retained mucosa. The mean operative time was 74.2 (38.0) min. Delayed bleeding and perforation were not observed.

CONCLUSION

Endoscopic mucosa-sparing lateral dissection is safe and feasible for the removal of gastric SMTs. The wound can be effectively closed using the retained mucosa and endoscopic clips, even if perforation has occurred. EMSLD provides an alternative to the resection of gastric SMTs, especially for tumors with a risk of intraoperative perforation.

Gastric Schwannoma: A Tumor Must Be Included in Differential Diagnoses of Gastric Submucosal Tumors

Gastric schwannoma (GS) is a rare neoplasm of the stomach. It accounts for 0.2% of all gastric tumors and is mostly benign, slow-growing, and asymptomatic. Due to its rarity, GS is not widely recognized by clinicians, and the precise differential diagnosis between GS and other gastric submucosal tumors remains difficult preoperatively. The present study reports a case of GS misdiagnosed as gastrointestinal stromal tumor and reviews the clinical, imaging, and pathological features, treatment, and follow-up of 221 patients with GS previously reported in the English literature. Although GS is rare, the case reported in the current study highlights the importance of including GS in differential diagnoses of gastric submucosal tumors. Furthermore, the findings of the review suggest that although many cases are asymptomatic, the most common symptoms are abdominal pain or discomfort, not gastrointestinal bleeding, and malignant GSs present with clinical symptoms more commonly. Although large-sample multicenter studies on the efficacy, safety, and oncological outcomes of minimally invasive techniques are required, the findings presented herein may be helpful for clinicians when diagnosing or treating GS.

Over-the-scope clip-assisted endoscopic full-thickness resection of epithelial and subepithelial GI lesions

BACKGROUND AND AIMS

Endoscopic full-thickness resection (EFTR) allows for definitive diagnosis and treatment of select subepithelial and epithelial lesions unsuitable to conventional resection techniques. Our aim was to evaluate the efficacy and safety of over-the-scope (OTS) clip-assisted EFTR for these lesions.

METHODS

Patients who underwent OTS clip-assisted EFTR between June 2014 and October 2015 were analyzed. The procedure involved (1) thermal marking of the periphery of the lesion; (2) lesion suction into the cap of either an OTSC (Ovesco Endoscopy AG, Tübingen, Germany) or Padlock clip (Aponos Medical Corp, Kingston, NH, USA) with or without triprong anchor retraction of the lesion; (3) clip deployment; and (4) en bloc resection of the lesion above the clip using an electrosurgical snare and/or knife. Data were abstracted for demographics, lesion features, histopathologic diagnoses, R0 resection (negative margins) status, and adverse events.

RESULTS

Nine patients (7 men) with a mean age of 63 ± 9.6 years were identified. The endoscopic findings included subepithelial lesions in the duodenum (n = 4), rectosigmoid colon (n = 2), stomach (n = 1), and postappendectomy appendiceal orifice polyps (n = 2). The mean lesion size was 8 ± 3 mm and the mean procedure time 53 ± 21 minutes. R0 resection was confirmed in all cases. The histopathologic diagnoses included neuroendocrine tumors (n = 6), sessile serrated adenomas (n = 2), and pancreatic heterotopia (n = 1). No adverse events were noted.

CONCLUSIONS

OTS clip-assisted EFTR is an effective and safe technique for the removal of select subepithelial and epithelial lesions that are not amenable to conventional resection techniques.

How best to manage gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are rare but most common nonepithelial tumor of gastrointestinal tract. They are often found incidentally on computed tomography and endoscopic investigations. Increasing knowledge of the pathogenesis of GISTs and the advent of tyrosine kinase inhibitors revolutionized the management of GISTs. The newer advanced endoscopic techniques have challenged the conventional surgery although the true efficacy and safety of endoscopic approach is not clear at this time. This review article focuses on pathogenesis, diagnosis and management of GISTs.

Endoscopic submucosal dissection for gastric gastrointestinal stromal tumors: a retrospective cohort study

BACKGROUND AND AIM

Endoscopic submucosal dissection (ESD) has been used to remove submucosal tumors. However, with regard to the potential malignant behavior of gastrointestinal stromal tumors (GISTs), whether ESD can be recommended for treatment is still controversial. Therefore, we evaluated the efficacy and safety of ESD for removal of GISTs in the muscularis propria (MP) layer and to assess the possible risk factors for a gastric-wall defect (GWD).

METHODS

For 168 GISTs located in the MP layer from 168 consecutive patients, the baseline information, complications, and therapeutic outcomes were recorded. Subsequently, risk factors for a GWD were analyzed.

RESULTS

Most GISTs (106/168) were located in the fundus of the stomach. Tumor shapes in 154 patients (91.7%) were regular, and the median size of the tumor was 1.5 (range 0.5-6.0) cm. The en bloc resection rate was 100% and the median procedure time was 46.5 (33-181) min. A GWD was observed in 71 patients (42.3%) and delayed bleeding occurred in 2 patients (1.2%), and they were treated by clips. A total of 117 patients with a GIST were at very low risk, 37 patients were at low risk, and 14 patients were at mild risk. No local recurrences or distant metastases were observed during a median follow-up of 25 (6-67) months. Univariate and multivariate logistic regression analyses identified the tumor type to be an independent risk factor for a GWD during ESD (odds ratio 29.82, 95% confidence interval 10.87-81.80, P < 0.001).

CONCLUSION

ESD is a safe and feasible method for gastric GISTs, especially for tumor types A and B. Endoscopic ultrasound can aid evaluation of the tumor type before ESD, which is an independent risk factor correlated with a GWD upon ESD.

Endoscopic resection of gastric submucosal tumors: A comparison of endoscopic nontunneling with tunneling resection and a systematic review

BACKGROUND/AIM

Endoscopic tunneling resection is a relatively novel endoscopic technology for removing gastric submucosal tumors. Our study aimed to compare the differences between tunneling and nontunneling resection for gastric submucosal tumors.

MATERIALS AND METHODS

Resections of gastric submucosal tumors (n = 97) performed from 2010 to 2015 at our endoscopy center were reviewed, and PubMed was searched for clinical studies on gastric submucosal tumor resection by endoscopic nontunneling and tunneling techniques.

RESULTS

At our endoscopy center, nontunneling (Group 1) and tunneling resection (Group 2) were performed for 78 and 19 submucosal tumors, respectively; median tumor diameters were 15 and 20 mm (P = 0.086), median procedural times were 50 and 75 min (P = 0.017), successful resection rates were 94.9% (74/78) and 89.5% (17/19) (P = 0.334), and en bloc resection rates were 95.9% (71/74) and 94.1% (16/17) (P = 0.569) in the Groups 1 and 2, respectively. Postoperative fever, delayed hemorrhage and perforation, hospitalization time, and hospitalization expense were statistically similar between the 2 groups. A literature review on gastric submucosal tumor resection suggested that the en bloc resection rates of the two methods for tumors with a median diameter of 15-30 mm were also high, and there were no relapses during the follow-up period.

CONCLUSIONS

Both endoscopic nontunneling and tunneling resection seem to be effective and safe methods for removing relatively small gastric submucosal tumors. Compared with endoscopic nontunneling, tunneling resection does not seem to have distinct advantages for gastric submucosal tumors, and has a longer mean operative time.

Endoscopic full thickness resection for gastric tumors originating from muscularis propria

AIM: To do systematic review of current literature for endoscopic full thickness resection (EFTR) technique for gastric tumors originating from muscularis propria.

METHODS: An extensive English literature search was done till December 2015; using PubMed and Google scholar to identify the peer reviewed original and review articles using keywords-EFTR, gastric tumor, muscularis propria. Human only studies were included. The references of pertinent studies were manually searched to identify additional relevant studies. The indications, procedural details, success rates, clinical outcomes, complications and limitations were considered. For the purpose of review, data from individual studies was combined to calculate mean. No other statistical test was applied.

RESULTS: A total of 9 original articles were identified. Four articles were from same institute and the time frames of these studies were overlapping. To avoid duplication of data, only the study with patients over the longest time interval was included and other three were excluded. In total six studies were included in the final review. In our systematic review, the mean success rate for EFTR of gastric tumors originating from muscularis propria was 96.8%. The mean procedure time varied from a minimum of 37 min to a maximum of 105 min. There was no reported mortality from the technique itself. The most common histological diagnosis was gastrointestinal stromal tumors and leiomyoma. Gastric wall defect closure by either metallic clips or over the scope clip (OTSC) had similar outcomes although experience with OTSC was limited to smaller lesions (< 3 cm).

CONCLUSION: EFTR is a minimally invasive technique to resect gastric submucosal tumors originating from muscularis propria with a high success rate and low complication rate.

[Endoscopic full-thickness resection]

Conventional endoscopic resection techniques such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) are powerful tools for the treatment of gastrointestinal (GI) neoplasms. However, those techniques are limited to the superficial layers of the GI wall (mucosa and submucosa). Lesions without lifting sign (usually arising from deeper layers) or lesions in difficult anatomic positions (appendix, diverticulum) are difficult - if not impossible - to resect using conventional techniques, due to the increased risk of complications. For larger lesions (>2 cm), ESD appears to be superior to the conventional techniques because of the en bloc resection, but the procedure is technically challenging, time consuming, and associated with complications even in experienced hands. Since the development of the over-the-scope clips (OTSC), complications like bleeding or perforation can be endoscopically better managed. In recent years, different endoscopic full-thickness resection techniques came to the focus of interventional endoscopy. Since September 2014, the full-thickness resection device (FTRD) has the CE marking in Europe for full-thickness resection in the lower GI tract. Technically the device is based on the OTSC system and combines OTSC application and snare polypectomy in one step. This study shows all full-thickness resection techniques currently available, but clearly focuses on the experience with the FTRD in the lower GI tract.

Hybrid NOTES: Combined Laparo-endoscopic Full-thickness Resection Techniques

Advances in laparoscopic surgery and therapeutic endoscopy have allowed these minimally destructive procedures to challenge conventional surgery. Because of its theoretic advantages and technical feasibility, laparoendoscopic full-thickness resection is considered to be the most appropriate option for subepithelial tumor removal. Furthermore, combination of laparoscopic and endoscopic approaches for treatment of neoplasia can be important maneuvers for gastric cancer resection without contamination of the peritoneal cavity if the sentinel lymph node concept is established. We are certain that the use of laparoendoscopic full-thickness resection will provide valuable experience that will allow operators to safely develop endoscopic full-thickness resection skills.

Endoscopic Submucosal Dissection (ESD) and Related Techniques as Precursors of "New Notes" Resection Methods for Gastric Neoplasms

Endoscopic full-thickness resection for subepithelial tumors is one of the more attractive proposed methods for less-invasive transluminal surgery but remains challenging in terms of safety and feasibility. Currently, laparoscopic endoscopic cooperative surgery is thought to be a more clinically acceptable approach. In targeting cancers, however, more advanced nonexposure techniques are required to avoid the risk of iatrogenic tumor seeding. By combining these techniques with possible regional lymphadenectomy using sentinel node navigation surgery, an ideal minimally invasive, function-preserving gastric resection can be achieved even in possible node-positive cancers. Further development for this type of advanced endoscopic surgery is expected.

Endoscopic Full-thickness Resection (EFTR) for Gastrointestinal Subepithelial Tumors

There has been booming interest in the endoscopic full-thickness resection (EFTR) technique since it was first described. With the advent of improved and more secure endoscopic closure techniques and devices, such as endoscopic suturing devices, endoscopists are empowered to perform more aggressive procedures than ever. This article focuses on the procedural technique and clinical outcomes of EFTR for gastrointestinal subepithelial tumors.

Clinical Control Study of Endoscopic Full-thickness Resection and Laparoscopic Surgery in the Treatment of Gastric Tumors Arising from the Muscularis Propria

BACKGROUND

Gastric stromal tumors arising from the muscularis propria are located in deeper layers. Endoscopic resection may be contraindicated due to the possibility of perforation. These tumors are therefore usually removed by surgical or laparoscopic procedures. This study evaluated the curative effects, safety and feasibility of endoscopic full-thickness resection (EFR) of gastric stromal tumors originating from the muscularis propria.

METHODS

This study enrolled 92 patients with gastric stromal tumors >2.5 cm originating from the muscularis propria. Fifty patients underwent EFR, and 42 underwent laparoscopic intragastric surgery. Operation time, complete resection rate, length of hospital stay, incidence of complications, and recurrence rates were compared in these two groups.

RESULTS

EFR resulted in complete resection of all 50 gastric stromal tumors, with a mean procedure time of 85 ± 20 min, a mean hospitalization time of 7.0 ± 1.5 days and no complications. Laparoscopic intragastric surgery also resulted in a 100% complete resection rate, with a mean operation time of 88 ± 12 min and a mean hospitalization period of 7.5 ± 1.6 days. The two groups did not differ significantly in operation time, complete resection rates, hospital stay or incidence of complications (P > 0.05). No patient in either group experienced tumor recurrence.

CONCLUSIONS

EFR technique is effective and safe for the resection of gastric stromal tumors arising from the muscularis propria.

Cutting edge of endoscopic full-thickness resection for gastric tumor

Recently, several studies have reported local full-thickness resection techniques using flexible endoscopy for gastric tumors, such as gastrointestinal stromal tumors, gastric carcinoid tumors, and early gastric cancer (EGC). These techniques have the advantage of allowing precise resection lines to be determined using intraluminal endoscopy. Thus, it is possible to minimize the resection area and subsequent deformity. Some of these methods include: (1) classical laparoscopic and endoscopic cooperative surgery (LECS); (2) inverted LECS; (3) combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique; and (4) non-exposed endoscopic wall-inversion surgery. Furthermore, a recent prospective multicenter trial of the sentinel node navigation surgery (SNNS) for EGC has shown acceptable results in terms of sentinel node detection rate and the accuracy of nodal metastasis. Endoscopic full-thickness resection with SNNS is expected to become a treatment option that bridges the gap between endoscopic submucosal dissection and standard surgery for EGC. In the future, the indications for these procedures for gastric tumors could be expanded.

Endoscopic full-thickness resection: Current status

Conventional endoscopic resection techniques such as endoscopic mucosal resection or endoscopic submucosal dissection are powerful tools for treatment of gastrointestinal neoplasms. However, those techniques are restricted to superficial layers of the gastrointestinal wall. Endoscopic full-thickness resection (EFTR) is an evolving technique, which is just about to enter clinical routine. It is not only a powerful tool for diagnostic tissue acquisition but also has the potential to spare surgical therapy in selected patients. This review will give an overview about current EFTR techniques and devices.

Endoscopic full-thickness resection for gastric submucosal tumors arising from the muscularis propria layer

AIM: To evaluate the efficacy, safety and feasibility of endoscopic full-thickness resection (EFR) for the treatment of gastric submucosal tumors (SMTs) arising from the muscularis propria.

METHODS: A total of 35 gastric SMTs arising from the muscularis propria layer were resected by EFR between January 2010 and September 2013. EFR consists of five major steps: injecting normal saline into the submucosa; pre-cutting the mucosal and submucosal layers around the lesion; making a circumferential incision as deep as the muscularis propria around the lesion using endoscopic submucosal dissection and an incision into the serosal layer around the lesion with a Hook knife; a full-thickness resection of the tumor, including the serosal layer with a Hook or IT knife; and closing the gastric wall with metallic clips.

RESULTS: Of the 35 gastric SMTs, 14 were located at the fundus, and 21 at the corpus. EFR removed all of the SMTs successfully, and the complete resection rate was 100%. The mean operation time was 90 min (60-155 min), the mean hospitalization time was 6.0 d (4-10 d), and the mean tumor size was 2.8 cm (2.0-4.5 cm). Pathological examination confirmed the presence of gastric stromal tumors in 25 patients, leiomyomas in 7 and gastric autonomous nerve tumors in 2. No gastric bleeding, peritonitis or abdominal abscess occurred after EFR. Postoperative contrast roentgenography on the third day detected no contrast extravasation into the abdominal cavity. The mean follow-up period was 6 mo, with no lesion residue or recurrence noted.

CONCLUSION: EFR is efficacious, safe and minimally invasive for patients with gastric SMTs arising from the muscularis propria layer. This technique is able to resect deep gastric lesions while providing precise pathological information about the lesion. With the development of EFR, the indications of endoscopic resection might be extended.