Endoscopic submucosal dissection for treatment of esophageal submucosal tumors originating from the muscularis propria layer

A nomogram prediction model for the risk of intra-abdominal infection after endoscopic full-thick resection of gastric submucosal tumors

Background

This study aimed to investigate the risk factors for complication of intra-abdominal infection (IAI) after endoscopic full-thickness resection of gastric submucosal tumors (GSMT) and to establish a nomogram prediction model for the occurrence of IAI.

Methods

Clinical data of patients with GSMT who underwent endoscopic full-thick resection (EFR) from January 2018 to July 2023 were retrospectively analyzed. The patients were divided into IAI and non-IAI groups according to whether IAI occurred during postoperative hospitalization. Univariate and multivariate logistic regression analyses were performed on the relevant clinical data of patients in the two groups to screen the independent influencing factors for the occurrence of IAI. The nomogram model was constructed based on the independent influencing factors. Model discrimination was assessed by the area under the curve (AUC) of the receiver operating characteristic (ROC) curve. The consistency of model-predicted risk with actual risk was evaluated using the Hosmer-Lemeshow goodness-of-fit test. The clinical performance of the nomogram model was evaluated using decision curve analysis.

Results

A total of 240 GSMT patients who underwent EFR procedures were finally included in this study, including 14 patients (5.83 %) in the IAI group and 226 patients in the non-IAI group. Univariate and multivariate logistic regression analyses showed that age (OR = 1.283, 95 % CI = 1.029-1.600), preoperative albumin (OR = 0.575, 95 % CI = 0.395-0.837), duration of operation (OR = 1.222, 95 % CI = 1.060-1.409), and hospitalization time (OR = 4.089, 95 % CI = 1.190-14.043) were independent influencing factors for the incidence of IAI in GSMT patients undergoing EFR surgery (P < 0.05). A Nomogram model was established based on the above factors. The Hosmer ⁃ Lemeshow test value of this model was 4.230 (P = 0.836). The AUC value of the predictive model was 0.992 (95 % CI: 0.983 to 1.000), with a C-index of 0.992 (95 % CI: 0.983-1.000), indicating that the nomogram model had good accuracy and discrimination. Decision curve analysis showed that the nomogram model had a good predictive performance.

Conclusions

Age, preoperative albumin, duration of operation, and hospitalization time were independent influences on the occurrence of IAI in GSMT patients undergoing EFR surgery. A nomogram model based on these factors had a high predictive efficacy and may provide a guiding intervention for the prevention of postoperative IAI in GSMT patients.

Optimal management options for esophageal gastrointestinal stromal tumors (E-GIST)

OBJECTIVE

To explore the different treatment modalities for esophageal gastrointestinal stromal tumors (E-GIST) and their respective applicability and clinical outcomes.

METHODS

This is a retrospective study in which consecutive patients diagnosed with E-GIST at our hospital from January 2017 to August 2023 were included. The clinical characteristics of all the patients as well as long-term quality of life were recorded and analyzed.

RESULTS

A total of 23 (12 males, 11 females) E-GIST patients with a mean age of 56.7 ± 12.0 years were included in this study. Common symptoms, including upper abdominal pain, acid reflux, and heartburn, accounted for over 60 % of cases. Fifteen patients underwent endoscopic resection, five patients underwent surgical resection, two patients underwent surgical resection after receiving preoperative imatinib therapy, and one patient received conservative management.

CONCLUSION

Different treatment strategies may be applied to the patients with E-GIST depending on the their clinical features. Our study provides insights into precise treatment for different patients. However, due to the rarity of the disease, it is challenging to collect a large sample size from a single center, necessitating more multicenter prospective large-scale studies.

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.

A scoring system to predict the technical difficulty of endoscopic resection for cardial submucosal tumors

BACKGROUND AND AIM

Endoscopic resection has been successfully used for the removal of digestive submucosal tumors (SMTs). However, the cardia has been considered a challenging location for endoscopic resection due to its narrow lumen and sharp angle. The objective of this study was to establish a clinical scoring model to grade the technical difficulty of endoscopic resection for cardial SMTs.

METHODS

A total of 246 patients who suffered cardial SMTs and received endoscopic resection were included in this retrospective study. All of them were randomized into the training cohort (n = 123) or internal validation cohort (n = 123). Potential predictors were analyzed using univariate analysis. Then, covariates with P < 0.05 were selected for the multivariate logistic regression model. The β coefficients from the logistic regression model were used to create a scoring system for technical difficulty prediction by rounding the score to the nearest integer of the absolute β coefficient value.

RESULTS

The clinical score consisted of the following factors: male gender (2 points), extraluminal growth (3 points), and maximum diameter ≥3 cm (3 points). The scoring model demonstrated good discriminatory power, with an area under the receiver operating characteristic curve of 0.860 and a 95% confidence interval of 0.763-0.958. The model also showed a good goodness of fit in the Hosmer-Lemeshow test (P = 0.979). In the training cohort, the probability of encountering technical difficulty in the easy (score = 0), intermediate (score = 1-3), difficult (score = 4-6), and very difficult (score >6) categories was 0, 6.8%, 33.3%, and 100.0%, respectively; similarly, in the validation cohort, it was 0, 5.6%, 22.2%, and 50.0%, respectively.

CONCLUSIONS

This scoring system could serve as a valuable tool for clinicians in predicting the technical difficulty of endoscopic resection for cardial SMTs.

Endoscopic resection of giant esophageal subepithelial lesions: experience from a large tertiary center

BACKGROUND AND AIMS

Increased reports on endoscopic resection (ER) of esophageal giant subepithelial lesions (g-SELs) have emerged in recent years. The aim of this study was to evaluate the efficacy, technical difficulty, and safety through our single-center experience.

METHODS

Seventy-five patients with g-SELs undergoing endoscopic resection were included in the training set. Clinicopathologic features, procedure-related characteristics, postprocedural outcomes, and follow-up data were analyzed. A predictive nomogram model for procedural difficulty was proposed based on the multivariable logistic regression analysis. Internal and external validations were conducted to verify the model performance.

RESULTS

The overall en bloc resection rate was 93.3%. Intraoperative and postoperative adverse events occurred in 7 (9.3%) and 13 (17.3%) patients, respectively. No recurrence or metastasis was observed. Thirty-two (42.7%) patients underwent a difficult procedure. Age (adjusted odds ratio [aOR], .915; P = .004), maximal tumor diameter ≥8 cm (aOR, 9.896; P = .009), irregular shape (aOR, 4.081; P = .053), extraluminal growth pattern (aOR, 5.419; P = .011), and submucosal tunneling endoscopic resection (aOR, .109; P = .042) were found to be statistically or clinically significant factors for predicting endoscopic resection difficulty, based on which a nomogram model was developed. Internal and external validations of the nomogram via receiver-operating characteristic curves and calibration curves achieved favorable results.

CONCLUSIONS

Endoscopic resection serves as a promising therapeutic option for esophageal g-SELs. A younger patient age, large tumor size, irregular shape, and extraluminal growth may indicate increased endoscopic resection difficulty, whereas a submucosal tunneling endoscopic resection procedure tends to be of lower difficulty. Our nomogram model performs well for predicting endoscopic resection difficulty for esophageal g-SELs.

Fibrin sealant for closure of mucosal penetration at the oesophagus or cardia during submucosal tunnelling endoscopic resection for gastrointestinal submucosal tumours

BACKGROUND AND STUDY AIM

To assess the efficacy and safety of a fibrin sealant for the prevention of leak resulting from mucosal penetration at the esophagus or cardia during a STER procedure to remove gastrointestinal submucosal tumors (SMTs).

PATIENTS AND METHODS

Between April 2014 and October 2022, a total of 290 patients with oesophageal or cardiac SMTs underwent STER at our centre. We retrospectively identified patients with oesophageal or cardia SMTs who underwent STER and experienced mucosal penetration of the cardia or oesophagus during the procedure. A total of 31 mucosal penetrations in 30 procedures were included. Of the 31 mucosal penetrations, 12 occurred in the cardia, and the other 19 occurred in the oesophagus. All 31 sites received the fibrin sealant to close the mucosal penetration. Clinical characteristics, procedure-related parameters, detailed data of the mucosal penetrations, and treatment outcomes using the fibrin sealant were reviewed for all 30 patients to assess the efficacy and safety of the fibrin sealant for closure of mucosal penetration at the cardia or oesophagus.

RESULTS

For the 31 mucosal penetrations, the mean size was 0.08 ± 0.06 cm2 (range 0.01-0.25 cm2). Mucosal closure using the fibrin sealant was performed successfully in all 31 mucosal penetrations. Of the 31 mucosal penetrations, clips were used in 13 cases. All 30 patients were discharged after a median of 7 days (range 4-20 day) postoperatively. During a mean 62 months (range 6-107 months) follow-up, all 31 mucosal penetrations successfully healed without the occurrence of infection, ulcer, oesophagitis, chest infection or abdominal infection.

CONCLUSION

For the closure of mucosal penetration during STER at the cardia or oesophagus, a fibrin sealant is both safe and efficacious. It is necessary to conduct more research on the viability, effectiveness, and safety of using a fibrin sealant to close wider mucosal penetrations.

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.

Muscular injury as an independent risk factor for esophageal stenosis after endoscopic submucosal dissection of esophageal squamous cell cancer

BACKGROUND AND AIMS

Stenosis after esophageal endoscopic submucosal dissection (ESD) has a high incidence, and muscular injury is an important risk factor for esophageal stenosis. Hence, this study aimed to classify muscular injury degrees and investigate their association with postoperative stenosis.

METHODS

This retrospective study included 1033 patients with esophageal mucosal lesions treated with ESD between August 2015 and March 2021. Demographic and clinical parameters were analyzed, and stenosis risk factors were identified using multivariate logistic regression. A novel muscular injury classification system was proposed and used to investigate the association between different muscular injury degrees and postoperative stenosis. Finally, a scoring system was established to predict muscular injury.

RESULTS

Of 1033 patients, 118 (11.4%) had esophageal stenosis. The multivariate analysis demonstrated that the history of endoscopic esophageal treatment, circumferential range, and muscular injury were significant risk factors for esophageal stenosis. Patients with type II muscular injuries tended to develop complex stenosis (n = 13 [36.1%], P < .05), and type II muscular injuries were more likely to predispose patients to severe stenosis than type I (73.3% and 92.3%, respectively). The scoring system showed that patients with high scores (3-6) were more likely to have muscular injury. The score model presented good discriminatory power in the internal validation (area under the receiver-operating characteristic curve, .706; 95% confidence interval, .645-.767) and goodness-of-fit in the Hosmer-Lemeshow test (P = .865).

CONCLUSIONS

Muscular injury was an independent risk factor for esophageal stenosis. The scoring system demonstrated good performance in predicting muscular injury during ESD.

Risk factors of perforation in gastric stromal tumors during endoscopic resection: a retrospective case-control study

BACKGROUND AND AIMS

Perforation is a common complication during endoscopic resection (ER) of gastric gastrointestinal stromal tumors (gGISTs) associated with secondary infections, sepsis, hospitalization time and cost. However, the risk factors of perforation remain controversial. This study aimed to investigate the risk factors for perforation during ER of gGISTs.

METHODS

This retrospective case-control study included consecutive patients with gGISTs who underwent ER between June 2009 and November 2021 at the Nanjing Drum Tower Hospital. Univariate and multivariate analyses were performed to investigate the risk factors for perforation. Sensitivity analyses with propensity scoring (PS) were performed to evaluate the stability of the independent effects.

RESULTS

In total, 422 patients with gGISTs were included. The following factors were associated with perforation during ER: in the non-intraluminal growth patterns (all confounders adjusted odds ratio [aOR]: 5.39, 95% CI 2.99-9.72, P < 0.001), in the gastric fundus (aOR 2.25, 95% CI 1.40-3.60, P = 0.007), sized ≥ 2 cm (aOR 1.70, 95% CI 1.04-2.77, P = 0.035), in the lesser curvature (aOR 0.12, 95% CI 0.05-0.27, P < 0.001), and in the gastric cardia (aOR 0.13, 95% CI 0.04-0.50, P = 0.003). The PS analysis confirmed the stable independent effects of these identified risk factors.

CONCLUSIONS

ERs of gGISTs in non-intraluminal growth patterns, in the gastric fundus, and with larger tumor size were independent risk factors for perforation. While tumors in the lesser curvature or gastric cardia were independent protective factor for perforation.

Clinical outcomes of endoscopic resection for the treatment of esophageal gastrointestinal stromal tumors: a ten-year experience from a large tertiary center in China

BACKGROUNDS

Esophageal gastrointestinal stromal tumors (E-GISTs) are extremely rare and surgical resection is the recommended approach. However, surgical resection usually causes severe trauma that may result in significant postoperative morbidity. Endoscopic resection (ER) has developed rapidly in recent years and has been widely used in gastrointestinal lesions. Nevertheless, the feasibility and efficacy of ER in the management of E-GISTs are unknown.

METHODS

Retrospective data were collected from January 2011 to December 2020 in a large tertiary center of China. Twenty-eight patients with E-GISTs treated by ER were included in the study.

RESULTS

Of the 28 patients, there were 21 males and 7 females, with a median age of 55 years (40-70 years). The median tumor size was 15 mm (5-80 mm). The technical success rate was 100% (28/28), while the en bloc resection rate was 96.4% (27/28). The median operation time was 35 min (10-410 min). Sixteen (57.2%) tumors were categorized into very low risk group, six (21.4%) into low risk group, and six (21.4%) into high risk group. Pathologists carefully examined margins of each lesion. There were 11 lesions (39.3%) determined as R0 resection and 17 lesions (60.7%) as R1 resection with positive margins. The median hospital stay was 2 days (range, 1-8 days). One patient suffered from hydrothorax and required drainage, leading to a major adverse event rate of 3.6% (1/28). There was no conversion to surgery, and no death occurred within 30 days after the procedure. Imatinib was given to two patients after ER under multidisciplinary team surveillance. During follow-up (median of 54 months, 9-122 months), no recurrences or metastasis were observed.

CONCLUSION

ER is safe and effective for E-GISTs and might become an optional choice in the future. Multicenter, prospective, large samples with long-term follow-up studies are still needed.

Efficacy and safety of esophageal submucosal tumors treated with internal traction method-assisted submucosal tunneling endoscopic resection: a single-center, single-blind, randomized controlled study

BACKGROUND AND OBJECTIVES

Submucosal tunnel endoscopic resection (STER) is an effective technique for treating esophageal submucosal tumors, but the efficacy and safety of treating esophageal submucosal tumors with internal traction method-assisted STER have not been determined. The objectives of this study were to assess the feasibility, safety, and efficacy of internal traction method-assisted STER for the removal of esophageal submucosal tumors.

PATIENTS AND METHODS

Eighty patients who underwent STER for esophageal submucosal tumors were included in the study. They were randomized and assigned to the two groups. The dual-knife method was used for STER. Forty patients underwent conventional STER (control group) and 40 underwent internal traction method-assisted STER in which self-made rubber band traction with clips was used (study group). In the study group, one end of the self-made rubber band was fixed on the surface of esophageal submucosal tumors with a clip, and the other end of the self-made rubber band was set on the anal side of the contralateral esophageal wall with a clip.

RESULTS

STER was successful in all cases. Lesion features and demographics were similar between the two groups. In addition, broad exposure of the submucosal tissue was obtained by applying tension to the self-made rubber band traction with clips. The en bloc resection rate and complete resection rate were both 100% in the study group. However, the en bloc resection rate and complete resection rate were 85.0% and 100%, respectively, in the control group. Complications, such as perforation and pneumomediastinum, were significantly reduced in the study group, and there was a significant difference in the number of occurrences of bleeding, operation duration, fasting time, and patient length of stay between the study group and control group (P < 0.05). During the mean 13.7 month follow-up, there were no patients with esophageal fistula, recurrence, or distant metastasis in either group.

CONCLUSIONS

This original study showed that esophageal submucosal tumors could be effectively and safely treated with internal traction method-assisted STER, and this technique might be superior to conventional STER due to its fewer complications, shorter operation duration, and shorter inpatient length of stay.

Risk factors of lymph node metastasis or lymphovascular invasion for superficial esophageal squamous cell carcinoma: A practical and effective predictive nomogram based on a cancer hospital data

Background

Lymphovascular invasion (LVI) is mostly used as a preoperative predictor to establish lymph node metastasis (LNM) prediction models for superficial esophageal squamous cell carcinoma (SESCC). However, LVI still needs to be confirmed by postoperative pathology. In this study, we combined LNM and LVI as a unified outcome and named it LNM/LVI, and aimed to develop an LNM/LVI prediction model in SESCC using preoperative factors.

Methods

A total of 512 patients who underwent radical resection of SESCC were retrospectively collected. Logistic regression and least absolute shrinkage and selection operator (LASSO) regression were adopted to identify the predictive factors of LNM/LVI. Integrated discrimination improvement (IDI) and net reclassification improvement (NRI) were calculated to select the potential predictive factors from the results of LASSO and logistic regression. A nomogram for predicting LNM/LVI was established by incorporating these factors. The efficacy, accuracy, and clinical utility of the nomogram were, respectively, assessed with the area under the curve (AUC), calibration curve, and decision curve analysis (DCA). Finally, the random forest (RF) algorithm was used to further evaluate the impact of these factors included in the nomogram on LNM/LVI.

Results

Tumor size, tumor location, tumor invasion depth, tumor differentiation, and macroscopic type were confirmed as independent risk factors for LNM/LVI according to the results of logistic regression, LASSO regression, IDI, and NRI analyses. A nomogram including these five variables showed a good performance in LNM/LVI prediction (AUC = 0.776). The calibration curve revealed that the predictive results of this nomogram were nearly consistent with actual observations. Significant clinical utility of our nomogram was demonstrated by DCA. The RF model with the same five variables also had similar predictive efficacy with the nomogram (AUC = 0.775).

Conclusion

The nomogram was adopted as a final tool for predicting LNM/LVI because its risk score system made it more user-friendly and clinically useful than the random forest model, which can help clinicians make optimal treatment decisions for patients with SESCC.

Thoracolaparoscopic esophagectomy for esophageal cancer with a cervical or abdominal incision to extract specimen

Surgery is the only curative approach for resectable esophageal cancer. This retrospective study was to investigate the immediate effect and operative complications of conventional and modified thoracolaparoscopic esophagectomy with a cervical or abdominal incision to extract specimen for the treatment of patients with esophageal cancer. Eighty-one patients were enrolled, among which 55 patients underwent conventional McKeown thoracolaparoscopic esophagectomy (conventional MTE) and 26 patients underwent modified MTE with a cerivical incision (modified MTE). The clinical, surgical, and postoperative data were analyzed. No significant (P > .05) difference was detected in the clinical data between two groups. The surgical procedure was successful in all patients (100%). The surgical time was significantly (P = .018) shorter in the conventional MTE group than in the modified MTE group (280 min vs 317 min). However, no significant (P > .05) difference was found in blood loss (200 mL vs 180 mL), intensive care unit (ICU) stay (31.3 ± 11.3 vs 25.2 ± 6.4 hours), first flatus after surgery (2.9 ± 1.9 vs 3.3 ± 1.6 days), postoperative hospital stay (12.9 ± 5.6 vs 12.6 ± 3.3 days), total number of lymph nodes dissected (27.9 ± 4.1 vs 26.7 ± 5.7), types of carcinoma, and pathological classification. No significant (P > .05) differences were detected in postoperative complications between the two groups. Assessment of postoperative pain using the visual analogue scale (VAS) score showed a significant (P < .05) difference in the VAS score at day 2 (4.81 ± 1.70 vs 3.87 ± 1.14) and day 3 (5.10 ± 0.83 vs 4.61 ± 1.12) between the conventional and modified MTE groups. The modified McKeown thoracolaparoscopic esophagectomy with only one cervical incision is more minimally invasive, more cosmetic, and less painful than the conventional approach.

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.

Comparison of endoscopic full-thickness resection and cap-assisted endoscopic full-thickness resection in the treatment of small (≤1.5 cm) gastric GI stromal tumors

BACKGROUND AND AIMS

With the increasing incidence of small GI stromal tumors (GISTs), endoscopic full-thickness resection (EFTR) and cap-assisted EFTR (EFTR-C) have been suggested as 2 effective resection methods. We aimed to compare the outcomes of EFTR and EFTR-C for the treatment of small (≤1.5 cm) gastric GISTs.

METHODS

This retrospective study included 67 patients who underwent EFTR and 46 patients who underwent EFTR-C at Nanjing Drum Tower Hospital. Clinicopathologic features, adverse events (AEs), and outcomes were compared between the 2 groups. Univariate and multivariate linear and logistic regressions were used to analyze the effects of the procedure on the therapeutic outcomes of patients and adjusted for covariates in the multivariate analysis.

RESULTS

The tumor size in the EFTR group tended to be larger (P = .005). The resection time in the EFTR-C group was shorter than that in the EFTR group (38.3 ± 20.7 minutes vs 15.0 ± 11.8 minutes, P < .001), which retained statistical significance with adjustment for the covariates (adjusted mean difference, 22.2; 95% confidence interval, 15.0-29.4; P < .001). The R0 resection rate of the EFTR group was 94.0% and of the EFTR-C group 97.8% (P = .355). The EFTR-C group was superior to the EFTR group in terms of perioperative therapeutic outcomes, AEs, and postoperative recovery. No recurrence occurred in the EFTR and EFTR-C groups.

CONCLUSIONS

EFTR-C was found to be the preferable technique for small (≤1.5 cm) gastric GISTs with shorter operation times, lower AEs, faster postoperative recovery, and shorter hospitalization times as compared with EFTR.

Endoscopic treatment can be a viable therapeutic option for esophageal gastrointestinal stromal tumors

BACKGROUND

Esophageal gastrointestinal stromal tumors(GISTs) are extremely rare. We sought to determine whether endoscopic treatment can be a viable therapeutic option for esophageal GISTs.

METHODS

A total of 20 cases with histological diagnosis of esophageal GISTs were obtained from our center between 2008 and 2020. Data on the clinicopathological features and treatment were recorded.

RESULTS

There were 9 males (45%) and 11 females (55%) in this study, with a median age of 56 years. The tumors preferentially occurred in the middle and lower parts of the thoracic esophagus (45 and 40%, respectively). The mean size of the tumors was 2.27 cm and mitotic index was no more than 5/50 high power field (HPF) in all patients. In this study, 11 patients received endoscopic treatment and nine patients underwent surgical resection. Tumors ranged from 0.6 to 4 cm in the endoscopic treatment patients and 0.5 to 7 cm in the surgical patients. There were no significant differences in gender, age, symptoms, tumor location, tumor size, mitotic index, and adjuvant imatinib therapy between the endoscopic treatment group and the surgery group (all p > .05). The Kaplan-Meier curve suggested that there was also no significant difference in disease-free survival between the two groups (p = .264).

CONCLUSIONS

Endoscopic treatment may be an option for the treatment of esophageal GISTs smaller than 5 cm with a mitotic index no more than 5/50 HPF.

Lymph node metastasis pattern and significance of left gastric artery lymph node dissection in esophagectomy for esophageal cancers

Purpose

To investigate the lymph node metastasis pattern and significance of dissection of the left gastric artery lymph nodes in radical en bloc esophagectomy for esophageal squamous carcinomas based on the lymphatic drainage pathway revealed by carbon nanoparticle labeling.

Materials and methods

Patients who underwent en bloc esophagectomy endoscopically were retrospectively enrolled. Carbon nanoparticles were injected in the submucosa of upper thoracic esophagus to label the relevant draining lymph nodes. The clinical data, lymph nodes dissected, surgical technique, and complications were analyzed.

Results

En bloc esophagectomy was successful in all 179 patients. Metastases to the left gastric artery lymph nodes were positive in 42 patients (23.5%) but negative in 137 (76.5%). The left gastric lymph nodes were labeled, whereas no celiac lymph nodes were labeled by carbon nanoparticles. A total of 4652 lymph nodes were resected, with 26 lymph nodes per patient. Seventy-three patients had lymph node metastasis (73/179). Seventeen patients had metastasis to the recurrent laryngeal nerve lymph nodes (9.5%). The metastasis rate of the lower thoracic esophageal cancer to the left gastric artery lymph nodes was 37.0%, significantly greater than that at the middle (15.4%) or upper (6.7%) thoracic segment. The lymph node metastasis rate was significantly (P < 0.05) increased with the length of the cancerous lesion, infiltration depth, and poor differentiation. Univariate analysis revealed that the metastasis rate to the left gastric artery lymph nodes was significantly (P < 0.05) associated with paraesophageal lymph node metastasis, para-cardial lymph metastasis, and TNM classification. Multivariate analysis indicated that cancer location (odds ratio 8.32, 95% confidence interval 2.12–32.24) was significantly (P < 0.05) associated with metastasis to the left gastric artery lymph nodes, with the cancer at the middle and lower thoracic segments significantly more than in the upper thoracic segment.

Conclusion

Certain patterns exist in lymph node metastasis of esophageal cancer, and in radical esophagectomy of esophageal cancers, dissection of the left gastric artery lymph nodes is necessary to prevent possible residual or metastasis of esophageal squamous carcinomas based on the lymphatic drainage pathway of esophageal carcinomas demonstrated by carbon nanoparticle labeling.

The Pathologic Confirmation in Subepithelial Tumors

Background/Aims: Subepithelial tumors (SETs) are small, mostly asymptomatic lesions with normal overlying mucosa, usually identified incidentally on endoscopy. The aim of this study was to evaluate the pathologic diagnosis of SETs, and to assess the diagnostic yield and impact of endoscopic submucosal dissection (ESD) biopsy on the management of patients with SETs.Materials and Methods: We included 52 subepithelial lesions in this study during the study period. Inclusion criteria included size of the SET >2 cm, and a gastrointestinal stromal tumor (GIST) that cannot be excluded using EUS. We performed an endoscopic biopsy of each SET using the ESD technique.Results: The mean diameter of the lesions was 24.15±6.0 mm. The diagnostic yield of this method was 96.15%. Among the 52 participants, 45 were located in the stomach, four in the esophagus, and three in the duodenum. The pathologic diagnoses included: 17 leiomyomas, 13 GISTs, 11 ectopic pancreases, two carcinomas, two inflammatory fibroid polyps, two Brunner’s gland hyperplasia, two lipomas, one glomus tumor, and two remained undiagnosed. The mean duration of the procedure was 13.44±2.41 minutes. Three complications were associated with the procedure.Conclusions: Deep biopsy via ESD is useful in determining the histopathologic nature of SETs. This method minimizes the need for unnecessary surgery in benign SETs.

Retrospective analysis of predictive factors for lymph node metastasis in superficial esophageal squamous cell carcinoma

This study aimed to identify the risk factors of lymph node metastasis (LNM) in superficial esophageal squamous cell carcinoma and use these factors to establish a prediction model. We retrospectively analyzed the data from training set (n = 280) and validation set (n = 240) underwent radical esophagectomy between March 2005 and April 2018. Our results of univariate and multivariate analyses showed that tumor size, tumor invasion depth, tumor differentiation and lymphovascular invasion were significantly correlated with LNM. Incorporating these 4 variables above, model A achieved AUC of 0.765 and 0.770 in predicting LNM in the training and validation sets, respectively. Adding macroscopic type to the model A did not appreciably change the AUC but led to statistically significant improvements in both the integrated discrimination improvement and net reclassification improvement. Finally, a nomogram was constructed by using these five variables and showed good concordance indexes of 0.765 and 0.770 in the training and validation sets, and the calibration curves had good fitting degree. Decision curve analysis demonstrated that the nomogram was clinically useful in both sets. It is possible to predict the status of LNM using this nomogram score system, which can aid the selection of an appropriate treatment plan.

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.

Submucosal Tunneling Endoscopic Resection

Minimally invasive endoscopic resection procedures continue to evolve, with submucosal tunneling endoscopic resection (STER) being a durable option for en bloc resection of submucosal tumors. Whether STER can be effectively used for larger (>3.5 cm) lesions remains to be seen. STER-ET is a novel approach for removal of extraluminal tumors, but data are currently limited to support its use.

Risk factors for complications after endoscopic treatment in Chinese patients with early esophageal cancer and precancerous lesions

BACKGROUND

This study aimed to analyze the risk factors for complications after endoscopic treatment of early esophageal cancer and precancerous lesions and provides evidence for developing preventive measures against these complications.

METHODS

The clinical data of patients with early esophageal cancer and precancerous lesions treated in the Department of Endoscopy, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences, and Peking Union Medical College from January 2009 to December 2015 were analyzed. The risk factors related to delayed bleeding, perforation, and stenosis were assessed.

RESULTS

Of 459 patients, 15 (3.3%) had delayed bleeding, 16 (3.5%) had perforation, and 82 (17.9%) had stenosis. Conservative treatment was performed for patients with bleeding and perforation, and endoscopic dilation was performed to relieve stenosis. The independent risk factors for delayed bleeding were lesion size (OR = 1.51, P = 0.020), circumferential diameter [odds ratio (OR) = 1.24, P = 0.037]. The kind of operation method [endoscopic submucosal dissection (ESD)/cap-based endoscopic resection (EMR-Cap): OR = 15.38, P = 0.013) was the independent risk factor for perforation. The independent predictors of stenosis were circumferential diameter (OR = 1.58, P < 0.001), lesion in the neck (OR = 0.12, P = 0.003), and surgical time (OR = 1.02, P = 0.007).

CONCLUSION

Few complications occur after the endoscopic treatment of early esophageal cancer and precancerous lesions which can be treated by endoscopic and conservative medical therapies. Strict operational training is required for ESD treatment.

Comparison of different endoscopic resection techniques for submucosal tumors originating from muscularis propria at the esophagogastric junction

Background

To compare the outcomes of submucosal tunneling endoscopic resection (STER) and submucosal excavation (ESE) for the treatment of submucosal tumors (SMTs) arising from the muscularis propria (MP) at the esophagogastric junction (EGJ).

Methods

A retrospective analysis of patients with SMTs at EGJ who underwent STER and ESE from October 2011 to October 2017 was performed. The outcomes evaluated were operation time, complete resection rate, adverse events, and tumor recurrence.

Results

Ninety patients were included in this study. Complete resection rates in the STER group were higher than those of the ESE group (100 vs. 92%, p < 0.05). For tumors ≤15 mm, both techniques achieved 100% complete resection rate; but for tumors > 15 mm, complete resection rate was higher in the STER group than the ESE group (100% vs. 77.8%, p < 0.05). Subgroup analyses revealed that the operation time of STER for in cardiac-gastric group was longer than that for ESE (145.14 ± 42.43 min vs. 70.32 ± 39.84 min, p <  0.05). The air leakage symptoms were more frequent in STER group (90.9% vs. 50.0%, p < 0.05). No tumor recurrence occurred in both the STER and ESE groups.

Conclusions

For SMTs ≤15 mm, both STER and ESE have similar satisfactory therapeutic outcomes. However, in the cardiac-gastric subgroup, STER had a longer operative time compared to the ESE procedure. For SMTs > 15 mm, STER is the preferred choice due to its higher complete resection rate.

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.

Submucosal Tunnel Endoscopic Resection for Esophageal Submucosal Tumors: A Multicenter Study

BACKGROUND

Submucosal tumors (SMTs) are primarily benign tumors, but some may have a malignant potential. Endoscopic submucosal dissection that has been used for removing esophageal SMTs could cause perforation. Submucosal tunnel endoscopic resection (STER) is an improved and an effective technique for treating esophageal SMTs.

AIMS

This study was conducted to evaluate the efficacy and safety of STER for treating esophageal SMTs.

METHODS

A retrospective study design was adopted to analyze the baseline characteristics, clinical outcomes, and follow-up data of patients with esophageal SMTs, which originated from the muscularis propria layer and were treated with STER from September 2011 to May 2018.

RESULTS

A total of 119 lesions were included from 115 patients who were successfully treated with STER. The mean age of the patients was 49.7 ± 10.7 years. The lesions were primarily located in the middle and lower esophagus. The mean size of the lesions was 19.4 ± 10.0 mm. The mean operation duration was 46.7 ± 25.6 min, and the mean duration of hospitalization was 5.9 ± 2.8 days. The total en bloc resection rate and the complete resection rate were 97.5% and 100%, respectively. Regarding complications, there were 9 (7.8%) cases of perforation, 2 (1.7%) cases of pneumothorax, and 9 (7.8%) cases of subcutaneous emphysema. Histopathological results revealed 113 (95.0%) cases of leiomyoma, 5 (4.2%) cases of gastrointestinal stromal tumors, and 1 (0.8%) case of a granular cell tumor. During the mean 15-month follow-up, there were no cases of recurrence and distant metastasis.

CONCLUSIONS

STER is a safe and feasible technique for treating esophageal SMTs originating from the muscularis propria layer.

A model based on endoscopic morphology of submucosal esophageal squamous cell carcinoma for determining risk of metastasis on lymph nodes

BACKGROUND

It is important to identify patients with esophageal squamous cell carcinoma (ESCC) in T1b stage that are the least likely to metastasize on the lymph nodes, to undergo endoscopic resection, especially for the patients unfit for esophagectomy. The relationship between endoscopic morphology and frequency of nodal metastasis has never been well studied. The aims of the study were to investigate the predictive value of endoscopic morphology for lymphatic metastasis, and to develop a risk stratification model in submucosal (T1b) ESCC.

METHODS

Pathologic variables of patients with T1b ESCC who underwent esophagectomy from 2006 through 2016 were collected and divided into training sets (patients between 2006 and 2011) and validation sets (patients between 2012 and 2016). The endoscopic morphology of the tumor was determined by analyzing endoscopic reports according to the Paris classification. The correlation between the clinicopathological factors and nodal metastasis was examined. A prediction model was developed to estimate the risk of metastasis using these predictors.

RESULTS

A total of 175 patients were included in this study. A tumor with an endoscopic shape of flat type (0-II type as Paris classification was defined) was significantly related to lower risk of lymphatic metastasis with the frequency of 15.5% (OR: 3.049, 95% CI: 1.363-6.819, P=0.005). The combination of endoscopic morphology with other pathologic characteristics including lymphovascular invasion, length of tumor, depth of tumor invasion into submucosa, and tumor differentiation improved the predictive value of the nodal metastasis. The risk stratification model was developed with a C-index of 0.726 (95% CI: 0.702-0.751), which identified a low risk subgroup with a lymph node rate of 7.2%.

CONCLUSIONS

Our results suggest that when a tumor is in flat shape (0-II type) it is related to a less lymphatic metastasis, and the combination of the endoscopic morphology with the other four pathologic variables can yield a more robust approach to predict the risk of lymphatic metastasis in submucosal ESCC.

Clinical Values of Dental Floss Traction Assistance in Endoscopic Full-Thickness Resection for Submucosal Tumors Originating from the Muscularis Propria Layer in the Gastric Fundus

BACKGROUND

Endoscopic full-thickness resection (EFTR) derived from endoscopic submucosal dissection has gradually been accepted and even promoted for the treatment of submucosal tumors (SMTs) originating from the muscularis propria (MP) layer. However, there are some difficulties when EFTR is used to treat MP lesions in the gastric fundus. This study intends to explore whether EFTR can be made simpler, safer, and more effective with the traction assistance of dental floss.

METHODS

The clinical data of patients (trial group) with lesions in the MP layer in the gastric fundus undergoing EFTR with traction assistance of dental floss at Zhongshan Hospital, in 2016, were reviewed retrospectively. The control group was matched with the trial group according to tumor size. The differences in tumor resection time, patient hospitalization time, and complication rate were evaluated.

RESULTS

There was no significant difference in the average age of the two groups, each of which comprised 24 cases (58.7 ± 11.8 years versus 56.6 ± 7.9 years, t = 0.663, P = .511). However, there was a statistically significant difference in the operative time between the two groups (10.8 ± 2.8 minutes versus 19.0 ± 4.7 minutes, t = 7.298, P < .05). There was no statistically significant difference in the length of the postoperative hospital stay (3.2 ± 0.5 days versus 3.2 ± 0.5 days, t = 0.291, P = .772). In the trial group, there were 19 cases of gastrointestinal stromal tumors (group 1) and 5 cases of leiomyoma. The control group had similar results. Neither group experienced postoperative delayed bleeding, perforation, or other complications.

CONCLUSIONS

When EFTR is used to treat SMTs originating from the MP in the gastric fundus, dental floss traction assistance can relieve the tumor boundary to simplify the surgical procedure and save the operation time.

Low-dose spectral insufflation computed tomography protocol preoperatively optimized for T stage esophageal cancer - preliminary research experience

AIM

To evaluate the T stage of esophageal squamous cell carcinoma (ESCC) using preoperative low-dose esophageal insufflation computed tomography (EICT).

METHODS

One hundred and twenty ESCC patients confirmed by surgery or esophagoscopy were divided into three groups. Groups B and C were injected with 300 mgI/kg contrast medium for automatic spectral imaging assist (GSI assist), while group A underwent a conventional 120 kVp computed tomography (CT) scan with a 450 mgI/kg contrast medium injection. EICT was performed in group C. Group A was reconstructed with filtered back projection, and groups B and C were reconstructed with 50% adaptive statistical iterative reconstruction. The contrast-to-noise ratio of lesion-to-mediastinal adipose tissue and the radiation dose were measured. Specific imaging features were observed, and T stage ESCCs were evaluated.

RESULTS

The sensitivity and accuracy of the T1/2 stage were higher in group C than in groups A and B (sensitivity: 43.75% vs 31.82% and 33.33%; accuracy: 54.29% vs 46.67% and 52.50%, respectively). With regard to the T3 stage, the sensitivity and specificity in group C were higher than those in groups A and B (sensitivity: 56.25% vs 41.17% and 44.44%; specificity: 73.68% vs 67.86% and 63.64%, respectively). The diagnostic sensitivity, specificity and accuracy of the T4 stage were similar among all groups. There were no significant differences in volume CT dose index [(5.91 ± 2.57) mGy vs (3.24 ± 1.20) vs (3.65 ± 1.77) mGy], dose-length product [(167.10 ± 99.08) mGy•cm vs (113.24 ± 54.46) mGy•cm vs (117.98 ± 32.32) mGy•cm] and effective dose [(2.52 ± 1.39) vs (1.63 ± 0.76) vs (1.73 ± 0.44) mSv] among the groups (P > 0.05). However, groups B and C received similar effective doses but lower iodine loads than group A [(300 vs 450) mgI/kg].

CONCLUSION

EICT combined with GSI assist allows differential diagnosis between the T1/2 and T3 stages. The ability to differentially diagnose the T3 and T4 stages of medullary ESCC can be improved by quantitatively and qualitatively analyzing the adipose tissue in front of the vertebral body.

Clinical Analysis of Endoscopic Submucosal Dissection for the Synchronous Multiple Primary Early Cancers in Esophagus and Stomach: 12 Cases Report

OBJECTIVE

With the improvement of endoscopic diagnosis, the discovery rate of the synchronous multiple primary early cancers in esophagus and stomach is gradually increased, while the traditional surgery bringing serious damages. Endoscopic submucosal dissection (ESD) has become the first treatment option of early cancer in the digestive tract partly. This study intends to explore the feasibility, safety, and effectiveness of ESD in the treatment of the synchronous multiple early gastric cancer or precancerous lesions in the esophagus and stomach.

METHODS

From January 2008 to December 2016, data of 12 patients with early esophageal cancer and early gastric cancer treated by ESD in the Endoscopy Center of Zhongshan Hospital, Fudan University were reviewed. We analyzed the patient's history, the size of esophageal and gastric lesions, pathological results, the results of complete or curative resection, and so on.

RESULTS

Among the 12 patients described in this study, all were diagnosed with synchronous multiple primary early cancers in the esophagus and stomach. Lesions were removed by ESD in 10 cases at the same time and were removed by stage in 2 cases. The complete resection rate was 100% (24/24), and the curative resection rate was 100% (24/24). Postoperative esophageal stricture occurred in 2 cases, which improved after dilation. Median follow-up time was 30 (8-115) months, when 9 patients survived and 3 patients died. However, the cause of death was not associated with treatment of this disease.

CONCLUSION

ESD is a minimally invasive endoscopic surgery, which can be used as a method of treating synchronous multiple primary early cancers in the esophagus and stomach.

Comparison between submucosal tunneling endoscopic resection and video-assisted thoracoscopic enucleation for esophageal submucosal tumors originating from the muscularis propria layer: a randomized controlled trial

BACKGROUND AND AIMS

Surgical resection is considered the first treatment option for submucosal tumors (SMTs) originating from the muscularis propria layer while submucosal tunneling endoscopic resection (STER) is proved to be a safe and effective method for treating SMTs. This study aimed to compare video-assisted thoracoscopic enucleation (VATE) with STER for treating esophageal SMTs.

METHODS

Sixty-six patients with small esophageal SMTs were prospectively randomized from July 2014 to December 2015. After exclusion of 8 patients, 58 subjects scheduled for STER or VATE were enrolled. Clinicopathological, endoscopic, and adverse events (AEs) data were collected and analyzed between STER and VATE.

RESULTS

Forty-six males and 12 females with a mean age of 46.1 ± 9.4 years were randomized to the STER (n = 30) and VATE (n = 28) groups, respectively. Demographics and lesion features were similar between the two groups. Median procedure time was shorter in the STER group than the VATE group (44.5 vs. 106.5 min, P < 0.001); cost was lower in the STER group (4499.46 vs. 6137.32 USD, P = 0.010). Median decrease in hemoglobin levels post-procedure was - 1.6 g/L in the STER group and 14.7 g/L after VATE (P = 0.001). Lower postoperative pain scores were found in the STER group compared with the VATE group (2 vs. 4, P < 0.001). No recurrent or residual tumors were found in either group. En bloc resection rates, complete resection rates, hospital times, and post-procedure AEs were similar between two groups. The en bloc resection rates for SMTs < 20.0 mm were 100% in both groups while STER achieved only 71.4% en bloc resection rate for SMTs ≥ 20.0 mm.

CONCLUSION

STER and VATE are comparably effective for esophageal SMTs; however, STER is superior to VATE with shorter operation time and decreased cost, and seems safer than VATE. STER is recommended for SMTs < 20.0 mm while VATE is recommended for SMTs with a transverse diameter > 35.0 mm. Clinical trail registration statement: This study is registered at http://www.chictr.org.cn/showproj.aspx?proj=4814 . The registration identification number is ChiCTR-TRC-14004759. The registration date is April 30, 2014.

A promising Forcep Strip Method for gastrointestinal subepithelial tumors originating from the muscularis propria

BACKGROUND

Subepithelial tumors (SETs) originating from the muscularis propria layer are unlikely to be resected completely and safely. We developed the Forcep Strip Method (FSM) for the resection of SETs in the stomach.

AIMS

This study aimed to evaluate the feasibility and safety of the FSM.

METHODS

Endoscopic SET resection using electrical forceps was performed in 11 consecutive patients with clinical indications for lesion removal. Following injection around the tumor, the adjacent mucosa or submucosa was grasped with the hot forceps and pulled away to form a "tent". The tumor was dissected from the muscularis propria layer and carefully removed using coagulating forceps.

RESULTS

The FSM was successful in 10 of the 11 patients in the series; one patient required surgery due to respiratory depression during the procedure. The complete resection rate was 100% and no major complications including bleeding and perforation occurred. Mean procedure time was 39.3 ± 14.7 min, mean hospitalization time was 5.0 ± 1.2 days, and mean tumor size was 17.1 ± 4.7 mm.

CONCLUSION

FSM was found to be an easy, safe, and effective procedure for the treatment of gastric SETs originating from the muscularis propria layer.

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.

Factors affecting the effectiveness and safety of submucosal tunneling endoscopic resection for esophageal submucosal tumors originating from the muscularis propria layer

BACKGROUND AND AIMS

Submucosal tunneling endoscopic resection (STER) has been proved to be effective and safe for esophageal submucosal tumors (SMTs) originating from the muscularis propria (MP) layer. This study was aimed to further evaluate the effectiveness, safety, and influencing factors especially the types of mucosal incision of STER in a larger population.

METHODS

A total of 89 patients undergoing STER with esophageal SMTs were retrospectively enrolled in this study from May 2012 to November 2016. Clinicopathological, endoscopic, and adverse events (AEs) data were collected and analyzed. Different incision methods were compared to evaluate the optimum incision method.

RESULTS

There were 27 females and 62 males with mean age of 46.5 ± 10.3 years. The medium size of the tumors was 16.0 mm (ranging 10.0-60.0 mm). Inverted T incisions were made in 29 (32.6%) patients, transverse incisions in 12 (13.5%) while longitudinal incisions in 48 (53.9%). En bloc resection was achieved in 70 (78.7%) patients. The residual rate was 1.1% (1/89), and no recurrence was noted even after piecemeal resection. The rate of AEs was 21.3% (19/89), and all of the AEs were cured without intervention or treated conservatively without the need for surgery. The en bloc resection rate was comparable among the three incision groups (P = 0.868); however, the incidence of AEs in the inverted T incision was lower than that in the longitudinal incision (P = 0.003). Fewer clips were used in the inverted T incision group than in the transverse incision group (P = 0.003).

CONCLUSIONS

Although STER failed to achieve en bloc resection in 21.3% patients, it was still an effective therapy owing to low residual rate and no recurrence rate after piecemeal resection. STER was safe with no severe AEs; however, minor AEs were common. Inverted T incision seems to be the optimum entry point.

Short- and Long-Term Outcomes of Endoscope-Assisted Laparoscopic Wedge Resection for Gastric Submucosal Tumors Adjacent to Esophagogastric Junction

BACKGROUND

Laparoscopic wedge resection (LWR) is used to treat gastric submucosal tumors (SMTs). However, LWR can injure the cardia if tumors are near the esophagogastric junction (EGJ), resulting in gastric stenosis. This study's purpose was to summarize our experience with endoscope-assisted LWR for gastric SMTs within 3 cm of the EGJ and to verify the procedure's feasibility and safety.

METHODS

Data from 91 consecutive patients with gastric SMTs within 3 cm of the EGJ who underwent endoscope-assisted LWR at our hospital from 2007 to 2017 were obtained from a prospectively maintained database. The clinicopathological results, perioperative data, and long-term follow-up data were analyzed.

RESULTS

All patients successfully underwent endoscope-assisted LWR. The mean distance from tumor to EGJ was 2.43 ± 0.80 cm. Eighty-two patients underwent laparoscopic exogastric wedge resection (LEWR) and nine underwent laparoscopic transgastric wedge resection (LTWR). Mean operative time was 112.4 ± 48.8 min; mean blood loss was 36.8 ± 53.5 ml. Mean time to first flatus was 2.04 ± 0.68 days. Mean time to liquid intake was 2.53 ± 0.85 days. Mean postoperative hospital stay was 4.97 ± 1.80 days. Three patients (3.3%) had postoperative complications, all Clavien-Dindo grade I. The mean maximum tumor diameter was 3.00 ± 1.96 cm (range 0.5-10). LTWR was used more often than LEWR for SMTs in the posterior wall, those with intraluminal growth, and those closer to the EGJ. The mean follow-up time was 36.86 ± 29.73 months (range 3-126). There was no stenosis of EGJ or tumor recurrence. Sixteen patients (17.6%) complained of upper gastrointestinal symptoms during the follow-up, which were all relieved by usage of acid suppressive medications.

CONCLUSIONS

Endoscope-assisted LWR is safe, feasible, and effective for gastric SMTs near the EGJ. LTWR is preferable to LEWR for gastric SMTs in the posterior wall, those with intraluminal growth, and those closer to the EGJ.

Efficacy and safety of endoscopic submucosal dissection for submucosal tumors of the colon and rectum

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) of colorectal submucosal tumors (SMTs) is becoming increasingly common; however, there have been few large consecutive studies analyzing its therapeutic efficacy and safety. The aim of this study was to evaluate the efficacy, safety, and long-term outcomes of ESD for colorectal SMTs.

METHODS

This retrospective study included 412 consecutive patients with colorectal SMTs who underwent ESD at the Zhongshan Hospital of Fudan University from January 2008 to July 2014. Tumor histopathology, completeness of resection, adverse events, tumor recurrence, and distant metastasis were analyzed.

RESULTS

Complete resection was achieved for 358 lesions (86.9%). Thirteen patients had serious adverse events (3.2%) including bleeding and perforation, and 28 patients (6.8%) had post-ESD electrocoagulation syndrome (PEECS). Because more ESDs for colorectal SMTs were performed by endoscopists, the rate of complete resection increased (78.5% vs 88.5%), and the rate of serious adverse events decreased (9.2% vs 2.0%). SMTs in the colon increased the risk of incomplete resection (19.6% vs 11.3%), serious adverse events (8.7% vs 1.6%), and PEECS (16.3% vs 4.1%). SMTs originating from the muscularis propria and sized ≥20 mm increased the rate of PEECS (22.7% vs 5.9% and 31.3% vs 5.8%, respectively).

CONCLUSION

ESD is effective for resection of colorectal SMTs and rarely causes serious adverse events. Tumor location and the experience of endoscopists influence the complete resection rate and the development of serious adverse events. ESD is feasible for large tumors and tumors in the muscularis propria, but this is associated with relatively high risks of adverse events.

Safety and efficacy of endoscopic submucosal dissection of large (≥3 cm) subepithelial tumors located in the cardia

BACKGROUND

Upper gastrointestinal subepithelial tumors (SETs) may harbor potential malignancy. Although it is well recognized that large SETs should be resected, the treatment strategy remains controversial. Compared to surgical resection, endoscopic resection has many advantages such as less invasive, shorter hospital stay, lower costs, and better quality of life. However, Endoscopic resection of large SETs in the cardia is challenging. The purpose of this study was to evaluate the safety and efficacy of endoscopic submucosal dissection (ESD) in the treatment of such SETs.

METHODS

A total of 41 patients with large SETs (≥3 cm in diameter) located in the cardia were involved in the study. All patients underwent ESD. Data on therapeutic outcomes and follow-up were collected, for analysis of risk factors of complication rates.

RESULTS

The average tumor size was 4.7 ± 1.7 cm. The average procedure time was 69.3 ± 32.7 min and the average postoperative hospital stay was 3.5 ± 1.1 days. A total of 41 tumors were removed successfully, in which 35 were leiomyomas, three were gastrointestinal stromal tumors, two were lipomas, and one was gastritis cystica profunda. The en bloc resection rate was 90.2%, and was significantly higher for tumors with a round or oval shape (100%) than for those with an irregular shape (75.0%) (P < 0.05). Five patients experienced complications (12.2%), all of which were managed conservatively. The complication rates were significantly higher in patients with a tumor originating from the deep muscularis propria layer and demonstrating a trans-cardia growth pattern. No residual or tumor recurrence was observed and no stricture occurred during the follow-up period (average, 26.7 ± 18.4 months).

CONCLUSIONS

ESD is safe and effective to curatively remove most large SETs in the cardia, and may serve as an accurate histopathology measurement to direct future therapy.

Current status of submucosal tunneling endoscopic resection for gastrointestinal submucosal tumors originating from the muscularis propria layer

Gastrointestinal submucosal tumors (SMTs) have been increasingly identified via the use of endoscopic ultrasonography, and removal is often recommended for SMTs that are >2 cm in diameter or symptomatic. Submucosal tunneling endoscopic resection (STER), also known as submucosal endoscopic tumor resection, endoscopic submucosal tunnel dissection or tunneling endoscopic muscularis dissection, is a novel endoscopic technique for treating gastrointestinal SMTs originating from the muscularis propria layer, and has been demonstrated to be effective in the removal of SMTs with a decreased rate of recurrence by clinical studies. STER may be performed for patients with esophageal or cardia SMTs, and its application has expanded beyond these types of SMTs due to modifications to the technique. The present study reviewed the applications, procedure, efficacy and complications associated with STER.

Endoscopic Submucosal Tunnel Dissection for Upper Gastrointestinal Submucosal Tumors Originating from the Muscularis Propria Layer: A Single-Center Study

BACKGROUND/AIMS

In recent years, endoscopic submucosal tunnel dissection (ESTD) has gained popularity worldwide. The aim of this study was to evaluate the safety and efficacy of ESTD in treating upper gastrointestinal submucosal tumors (SMTs) in a large-volume endoscopic center.

METHODS

Patients with SMTs were enrolled in this study between January 2012 and January 2015. Demographic data, clinical data, and treatment outcome were collected and analyzed.

RESULTS

Seventy SMTs originating from the muscularis propria (MP) layer were identified in 69 patients. All patients successfully underwent the ESTD procedure. The mean procedure time was 49.0±29.5 minutes, and the mean tumor size was 18.7±7.2 mm. Among all lesions, the majority (70.0%) were located in the esophagus, 12.9% in the cardia, and 17.1% in the stomach. Complete resection was achieved in 67 lesions (95.7%). Perforation occurred in three patients (4.3%), who were treated by endoclips. Pneumothorax occurred in two patients (2.9%) and was successfully managed by thoracic drainage. During a median follow-up of 18.1 months, patients were free of local recurrence or distant metastasis.

CONCLUSIONS

Our results demonstrated the feasibility and safety of ESTD in treating upper gastrointestinal SMTs originating from the MP layer. Large-scale comparative studies with other treatment methods should be conducted in the future.

Comparison of endoscopic submucosal tunneling dissection and thoracoscopic enucleation for the treatment of esophageal submucosal tumors

BACKGROUND AND AIMS

Endoscopic submucosal tunneling dissection (ESTD) has been proved to be safe and effective for removal of esophageal submucosal tumors (SMTs) and can maintain the mucosal integrity compared with other endoscopic methods. The aim of the study was to estimate the safety and efficacy of ESTD as well as compare its efficacy with thoracoscopic enucleation for esophageal SMTs, which is used increasingly as a minimally invasive approach.

METHODS

We retrospectively collected the clinical data of patients with esophageal SMTs <40 mm who underwent ESTD or thoracoscopic enucleation at Nanfang Hospital between January 2008 and August 2016. Epidemiologic data (sex, age), tumor location, tumor size, en bloc resection rate, adverse events, pathologic results, length of postoperative hospital stay, and cost were compared between ESTD and thoracoscopic enucleation.

RESULTS

A total of 126 patients were included. A total of 74 patients underwent ESTD, and the other 52 underwent thoracoscopic enucleation. There was no significant difference between the 2 groups in sex, age, tumor size, hospitalization expense, infection, adverse events, and en bloc resection rate (P < .05). However, patients in the ESTD group had a shorter operating time, less estimated blood loss, shorter length of postoperative hospital stay, and lower chest pain level (P < .05). Kaplan-Meier curves for disease-free survival also showed no statistically significant difference between ESTD and thoracoscopic enucleation groups during the median follow-up of 19.5 and 42 months, respectively.

CONCLUSIONS

The treatment efficacy was comparable between the ESTD and thoracoscopic enucleation for esophageal SMTs <40 mm. However, there was a significant advantage in the ESTD group for a shorter operating time, reduced postoperative chest pain, and shorter hospitalization.

Hyperechoic demarcation line between a tumor and the muscularis propria layer as a marker for deciding the endoscopic treatment of gastric submucosal tumor

Minimally invasive endoscopic resection has been rapidly adopted as a new technique for treating patients with gastric submucosal tumors (SMTs) originating in the muscularis propria (MP) layer. This study was conducted to evaluate the information obtained from endoscopic ultrasonography (EUS) to determine the appropriate endoscopic dissection method for treating SMTs originating in the MP layer. Between February 2014 and May 2016, a total of 50 patients with gastric SMTs originating in the MP layer were enrolled in this study. The clinical features of the patients and their endoscopic, EUS, and histopathologic findings, as well as their postoperative follow-up data, were analyzed in this retrospective study. The mean age of the patients was (55.0±10.2) years, and the male/female ratio was 17:33. Endoscopic submucosal dissection (ESD) was performed on 43 patients and an endoscopic full-thickness resection (EFR) was performed on seven patients. The most frequent location for an SMT was in the upper body region of the stomach (n=16), and the most common pathological diagnosis was a gastrointestinal stromal tumor (GIST) (n=32). The overall rates for complete resection were 95.3% (41/43) and 100.0% (7/7) when the SMTs were treated by ESD and EFR, respectively. The presence of a complete tumor capsule was significantly associated with a complete resection (P=0.001). Of the cases treated by ESD, nine patients developed perforation, one of whom required laparoscopic surgery. The remaining patients were closed with clips or purse-string sutures. The presence of an MP2-type tumor (P=0.018) and a wide connection with the MP layer (P=0.044) were significantly associated with perforation. A preoperative evaluation of the integrity and the location of a tumor capsule and the length of the tumor connection with the MP layer by EUS can improve the complete resection rate and reduce the occurrence of intraoperative complications. Tumors with a complete capsule originating from the superficial MP layer or with a narrow connection with the MP layer are appropriate candidates for treatment by ESD.

Endoscopic submucosal tunnel dissection of upper gastrointestinal submucosal tumors: A comparative study of hook knife vs hybrid knife

AIM

To compare the efficacy and safety of a hook knife (HO) with a hybrid knife (HK) during endoscopic submucosal tunnel dissection (ESTD) procedure.

METHODS

Between August 2012 and December 2015, the ESTD procedure was performed for 83 upper GI submucosal lesions, which originated from the muscularis propria layer identified by upper endoscopy and endoscopic ultrasonography. Of these, 34 lesions were treated by a HO, whereas 49 lesions were treated by a HK. Data regarding age, gender, presenting symptoms, tumor location and size, procedure time, complications, en bloc resection rate and others were analyzed and compared between the two groups.

RESULTS

There were no significant differences in the age, gender, presenting symptoms and tumor location between the two groups. ESTD was successfully completed in all the patients, and no case was converted to laparoscopy. The mean procedure time was significantly shorter in the HK group than in the HO group (41.3 ± 20.3 min vs 57.2 ± 28.0 min, P = 0.004). The mean frequency of device exchange was 1.4 ± 0.6 in the HK group and significantly less than 3.3 ± 0.6 in the HO group (P < 0.001). The differences in tumor size and histopathological diagnoses were not significant between the two groups (P = 0.813, P = 0.363, respectively). Both groups had an equal en bloc resection rate and complete resection rate. Additionally, the complication rate was similar between the two groups (P = 0.901). During the follow-up, no recurrence occurred in either group.

CONCLUSION

We demonstrate for the first time that HO and HK do not differ in efficacy or safety, but HK reduces the frequency of device exchange and procedure time.

Submucosal tunneling endoscopic resection of upper gastrointestinal tract tumors arising from muscularis propria

The management of incidentally discovered small upper gastrointestinal (GI) tract submucosal tumors (SMT) remains debatable. In this review, we summarize the evolving experience with submucosal tunneling endoscopic resection (STER) of upper GI SMTs originating from the muscularis propria. From 16 original studies, we reviewed a total of 703 patients with 736 lesions. Of these, 436 were located in the esophagus, 146 in the esophagogastric junction (EGJ) and 154 in the stomach. The composite complete resection rate (CRR) for STER of upper GI tumors arising from the muscularis propria layer was 99.8% (445/446). The composite CRR for STER of esophageal, EGJ and gastric SMTs arising from the muscularis propria layer was 100% (208/208),100% (78/78)and 100% (115/115), respectively. The composite en bloc resection rate (EBRR) for STER of upper GI tumors arising from the muscularis propria layer was 94.6% (679/718). The composite EBRR for STER of esophageal, EGJ and gastric SMTs arising from the muscularis propria layer was 98.6% (205/208), 96.2% (75/78) and 97.9% (95/97), respectively. Tumor recurrence rate was 0%. The reported complication rate for STER was high but the majority responded to conservative management. STER is a minimally invasive and efficacious alternative to surgery, especially for patients with small tumors (<3 cm). Careful selection of candidates remains crucial for excluding potentially malignant tumors.

Treatment of leakage via metallic stents placements after endoscopic full-thickness resection for esophageal and gastroesophageal junction submucosal tumors

OBJECTIVE

The objective of this study is to evaluate the feasibility and efficacy of endoscopic full-thickness resection (EFTR) and fully covered retrievable self-expandable metal stents (SEMSs) placement for this kind of tumors.

METHODS

A total of six consecutive patients, presenting with esophageal and GE junction SMTs, received EFTR and SEMSs placement at the our endoscopic center between January 2015 and June 2015. Their medical records were thoroughly investigated.

RESULTS

EFTR was performed successfully in all cases. The en bloc resection rate was 100%. The final pathological diagnoses were leiomyomas in all six cases. No patients developed delayed bleeding. SEMSs were placed immediately after EFTR during the same endoscopic session except patient #1. Complete healing of esophageal leakage after stent placement was achieved for 6/6 patients (100%) without the need for surgical interventions. Stent migration occurred in one patient. No residual tumor or tumor recurrence was observed during the follow-up period.

CONCLUSIONS

EFTR combined with fully covered retrievable self-expandable metallic stents placement is a feasible and effective new method for providing radical treatments for SMTs from the deep MP layer of esophagus and GE junction. Standardization of the procedure should be studied further.

Complications of endoscopic resection techniques for upper GI tract lesions

Adverse events can occur during and after the endoscopic resection of upper gastrointestinal lesions. Their incidence can be minimized through the adoption of preventive measures and their final outcomes can be optimized through prompt identification and adequate treatment. In this evidence-based review we describe the risk factors for adverse events, preventive measures to avoid them and their management when they occur. Algorithms of action are also provided. Oesophageal strictures can be prevented with corticosteroids (either locally injected or systemically administered) and treated with endoscopic dilatation. Bleeding can be minimized through the adoption of prophylactic coagulation and novel preventive measures are emerging and being evaluated. Bleeding management includes coagulation therapy, clips and haemostatic powders. Perforations can nowadays be successfully treated endoscopically in the majority of the cases and conservative treatment is associated with favourable outcomes although optimal management is unclear.

Comparison between submucosal tunneling endoscopic resection and video-assisted thoracoscopic surgery for large esophageal leiomyoma originating from the muscularis propria layer

BACKGROUND

Submucosal tunneling endoscopic resection (STER) has been proved to be safe and effective for removal of esophageal leiomyoma originating from the muscularis propria (MP) layer. However, there are still technical challenges for tumors ≥35 mm due to the limited space of the submucosal tunnel. The aim of the study was to estimate the safety and efficacy of STER for large esophageal leiomyoma originating from the MP layer as well as compare its efficacy with video-assisted thoracoscopic surgery (VATS), which is a standard procedure for treating esophageal leiomyoma.

METHODS

We retrospectively collected the clinical data of the patients with esophageal leiomyoma of 35-55 mm who underwent STER or VATS at our hospital between January 2010 and December 2014. Epidemiological data (gender, age), tumor location, tumor size, procedure-related parameters, complications, length of stay and cost were compared between STER and VATS.

RESULTS

A total of 31 patients were enrolled, and 18 patients underwent STER and the other 13 received VATS. There was no significant difference between the two groups in gender, age, tumor location, tumor size, complications and rate of en bloc resection (P > 0.05). However, patients in the STER groups had a shorter operation time, a less decrease in hemoglobin level, a shorter length of hospital stay and a decreased cost (P < 0.05). No recurrence was noted in the STER and VATS groups during a mean follow-up of 10.9 and 30.8 months, respectively.

CONCLUSIONS

The treatment efficacy was comparable between the STER and VATS for esophageal leiomyoma of 35-55 mm. However, STER is superior to VATS in a shorter operation time, a less decrease in hemoglobin level, a shorter length of hospital stay and a decreased cost.

Simulator training in gastrointestinal endoscopy - From basic training to advanced endoscopic procedures

Simulator-based gastrointestinal endoscopy training has gained acceptance over the last decades and has been extensively studied. Several types of simulators have been validated and it has been demonstrated that the use of simulators in the early training setting accelerates the learning curve in acquiring basic skills. Current GI endoscopy simulators lack the degree of realism that would be necessary to provide training to achieve full competency or to be applicable in certification. Virtual Reality and mechanical simulators are commonly used in basic flexible endoscopy training, whereas ex vivo and in vivo models are used in training the most advanced endoscopic procedures. Validated models for the training of more routine therapeutic interventions like polypectomy, EMR, stenting and haemostasis are lacking or scarce and developments in these areas should be encouraged.

Safety of Endoscopic Resection for Upper Gastrointestinal Subepithelial Tumors Originating from the Muscularis Propria Layer: An Analysis of 733 Tumors

OBJECTIVES

Although endoscopic resection is an accepted technique for upper gastrointestinal subepithelial tumors (SETs) originating from the muscularis propria (MP) layer, published data regarding its complications are highly variable and limited to small data series. This study aimed to analyze the safety of endoscopic resection in a large case series.

METHODS

A total of 726 consecutive patients with 733 upper gastrointestinal SETs originating from the MP layer underwent endoscopic resection from June 2005 to December 2014. The complete resection rate, perioperative perforation rate, and perioperative bleeding rate were the main outcome measurements.

RESULTS

The complete resection rate was 97.1%. Ninety-four patients had complications (12.9%), including 88 with perioperative perforations (12.1%), 13 with perioperative bleeding (1.8%), 5 with localized peritonitis (0.7%), and one with delayed bleeding (0.1%). Eleven patients required surgery; the others were treated endoscopically. Risk factors for incomplete resection were extensive connection of the tumor to the MP layer (P=0.007) and extraluminal growth (P=0.048). Risk factors for perioperative perforation were larger tumor size (≤2.0 cm vs. 2.1-3.0 cm vs. >3.0 cm, P=0.021), extraluminal growth (P=0.046), and extensive connection (P<0.001). A risk factor for perioperative bleeding was larger tumor size (P=0.045). No residual or recurrent lesions were detected during the follow-up period (median: 28 months).

CONCLUSIONS

Endoscopic resection is an effective and reasonably safe therapeutic method for treating/removing upper gastrointestinal SETs originating from the MP layer when managed by an experienced endoscopic team.

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.

Comparison of endoscopic submucosal dissection and surgery for the treatment of gastric submucosal tumors originating from the muscularis propria layer: a single-center study (with video)

INTRODUCTION

Endoscopic submucosal dissection (ESD) has been used for the treatment of gastric submucosal tumors (SMTs). This study aims to compare clinical outcomes of ESD versus laparoscopic wedge resection (LWR) for gastric SMTs.

METHODS

This is a retrospective cohort study. Patients with SMTs who underwent ESD or LWR were enrolled in this study at a university-affiliated hospital from January 2010 to October 2015. Preoperative endoscopic ultrasound and computed tomography were performed to determine origin of layer and growth pattern. Clinical outcomes including baseline demographics, tumor size, operation time, blood loss, hospital stay, cost, pathology and postoperative complications were compared.

RESULTS

From January 2010 to October 2015, 68 patients with SMTs received ESD and 47 patients with SMTs received LWR. There was no difference in age, gender, body mass index, origin of layer and proportion with symptoms between ESD group and LWR group. However, tumor size was significantly larger in the LWR group (37.1 mm) than in the ESD group (25.8 mm, P = 0.041). For patients with tumors smaller than 20 mm, ESD was associated with shorter mean operation time (89.7 ± 23.5 vs 117.6 ± 23.7 min, P = 0.043), less blood loss (4.9 ± 1.7 vs 72.3 ± 23.3 ml, P < 0.001), shorter length of hospital stay (3.6 ± 1.9 vs 6.9 ± 3.7 days, P = 0.024) and lower cost (2471 ± 573 vs 4498 ± 1257 dollars, P = 0.031) when compared with LWR. For patients with tumors between 20 mm and 50 mm, ESD was associated with shorter mean operation time (99.3 ± 27.8 vs 125.2 ± 31.5 min, P = 0.039), less blood loss (10.1 ± 5.3 vs 87.6 ± 31.3 ml, P < 0.001), shorter length of hospital stay (4.0 ± 1.7 vs 7.3 ± 4.5 days, P = 0.027) and lower cost (2783 ± 601 vs 4798 ± 1343 dollars, P = 0.033) when compared with LWR. There were no significant differences in terms of rates of en bloc resection, complete resection and complication and histological diagnosis regardless of tumor size.

CONCLUSIONS

ESD can achieve similar oncological outcomes when compared with surgery for treatment of gastric SMT smaller than 50 mm.