Comparison Of Endoscopic Submucosal Tunneling Dissection And Endoscopic Submucosal Excavation For The Treatment Of Gastric Subepithelial Tumors

Background and ObjectionAs endoscopic diagnosis for upper gastrointestinal diseases becomes more widespread,many subepithelial tumors(SETs)are being detected accidently.The most common pathology type is the GIST,followed by leiomyoma.The majority of SETs are considered to be benign;however,some of these neoplasms,especially gastrointestinal stromal tumors(GISTs)and those arising from the muscularis propria(MP)layer,do have malignant potential.Resection is frst-line treatment of large or symptomatic gastric SETs,SETs<2 cm were primarily subjected to follow-up observation according to the National Comprehensive Cancer Network(NCCN)guidelines.Conventional or endoscpic surgery resection is not only a therapeutic but also a diagnostic strategy.Conventional or laparoscopic resection for SETs has been established,yet certain limitations exist,such as post-operative stenosis or deformity,additional risk of bleeding and intraperitoneal contamination from gastric juice leakage.With the development and maturation of endoscopic technology recently,endoscopic resection has become the main approach for the treatment of upper gastrointestinal SETs.New technical advances,including endoscopic submucosal excavation(ESE),submucosal tunneling and endoscopic resection(STER),and endoscopic full-thickness resection(EFTR),are effective and safe tissue resection methods for SETs.ESE is technically similar to ESD and differs in the depth of excavation.In contrast to other procedures,STER neatly sidesteps the gas or digestive fluid leak considering that this technique can maintain mucosal integrity.Due to large lumen,high flexibility and unfixed position,STER in the stomach is more difficult than that in the esophagus.In the gastric fundus and lesser curvature,building the submucosal tunnel is challenging because of retroflexion of endoscope.This study aimed to compare the efficacy and safety of ESE with STER for gastric SETs.Methods and materialsWe retrospectively reviewed and collected the medical records of 235 consecutive cases with SETs removed by ESE or STER between January 2011 and April 2017.The inclusion criteria were as follows:(1)Gastric fundus SETs originated from the MP layer and diagnosed by endoscopic ultrasonography;(2)Informed consent was obtained prior to surgery.The exclusion criteria were as follows:(1)SETs with remote metastasis or without restriction of extraluminal growth and(2)serious accompanied diseases such as advanced malignant tumor and organ failure.Surgeries were main performed by doctor P1,P2,and P3.They are very skilled and experienced operators who had successfully performed more than a hundred ESD.Clinical characteristics were collected including sex,age,symptoms,tumor site,size and pathological results.Operation details were retrospectively assessed including operating time,significant adverse events,length of hospital stay after resection and hospital cost.Significant adverse events were defined as macroperforation or major bleeding.Macroperforation was defined as the absence of an intestinal wall requiring surgical intervention,pneumothorax and/or hydrothorax requiring therapeutic intervention and peritonitis.Major bleeding was defined as a significant bleeding requiring transfusion with>2 units of red blood cells or surgery or a significant postprocedure clinical symptom requiring endoscopy or surgery interventions.Postoperative hospital stay was defined as the time from the date of STER or ESE to the discharge date.Resection was defined as the excision of all gross disease,regardless of microscopic margins.En bloc resection was defined as the resection of tumors in 1 piece.Recurrence was defined as biopsy-proven recurrent SETs or a lesion deemed suspicious on cross-sectional imaging.All procedures were carried out in left lateral position under general anesthesia with endotracheal intubation.Carbon dioxide(C02)insufflation was used.ESE and STER were performed according to previously suggested protocols.ESE:Lesion boundaries were identified and marked.After injection of a 0.9%saline solution mixed with epinephrine(dilution rate 1:100,000)and indigo carmine dye or a solution mixed with sodium hyaluronate and glycerol fructose into the submucosal layer to lift the covering mucosal and submucosal layer off from the lesion,an initial incision was made from the regular mucosal layer in a regular interval by using a hook knife and/or insulated-tipped electrosurgical knife(IT knife).Submucosal dissection was done with a hook knife and/or insulated-tipped IT knife.After removal,the mucosal incision was closed by clips and coagulation of all visible vessels was performed by using a pair of coagulating forceps.STER:The mixed solution of 10 mL saline with 0.3%indigo carmine dye and epinephrine(dilution rate 1:100,000)was injected 4 to 5 cm proximal to the lesion.A 2-cm mucosal incision was made to gain entry to the submucosal layer,and a submucosal tunnel was created until the lesion was visible.After exposure of the SET,dissection was carefully performed along the margin of the tumor by using an IT knife along the margin.After dissection,the mucosal entry site was closed with standard hemostatic clips.After resection,preventive coagulation was routinely performed.After endoscopic resection of the tumor,a proton-pump inhibitor was routinely administered.Follow-up endoscopic examination was usually performed 1 and 3 months after the resection.A surveillance endoscopy was performed every year subsequently.The date of last follow-up,recurrence,and survival were collected.Statistical analysisQuantitive data(age,tumor size,etc.)were described as mean(SD),median and range and were compared by independent t test.Statistical differences between groups were analyzed by Chi square test for categorical variants(gender,complete resection rate,post-operative adverse events,etc.).Disease-free survival was assessed using Kaplan-Meier tests.All analyses were performed using SPSS 13.0(SPSS Inc.,Chicago,IL,United States)was used for statistical analysis,with P<0.05 considered statistically significant.ResultsA total of 235 consecutive cases were included,174 patients(87 male and 88 female with mean age about 47.2 ± 13.8 years)received ESE(ESE group),61 patients(32 male and 29 female with mean age about 46.5 ±10.9 years)received STER(STER group).In the ESE group,median tumor size was 15mm(7-50mm),procedure time was 60min(8-200min),postprocedural hospital stay was 6 days(2-17 days)and hospital cost was 26248 RMB(13173-66884 RMB).ESE was achieved in 162(93.1%)patients and failed in 12 patients.In the STER group,median tumor size was 22 mm(6-45mm),procedure time was 60min(20-250min),postprocedural hospital stay was 6 days(2-13 days)and hospital cost was 32551 RMB(11494-57665 RMB).STER was successfully completed in 55(90.2%)patients and failed in 6 paitents.A total of 74 cases with gastric fundus SETs from MP layer were included.One patient received STER but failed and then received ESE.A total of 20 patients underwent STER,and 54 underwent ESE.There was no significant difference between the 2 groups in sex,hospital stay and cost,operating time,significant adverse events and en bloc resection rate(P>0.05).However,patients who received STER had a larger tumor size(ESE versus STER,15[7-50]versus 25[12-40]mm;P<0.05).Kaplan-Meier curves for disease-free survival also showed no statistically significant difference between STER and ESE groups,during a median follow-up of 14(3-41)and 14(3-64)months,respectively.ConclusionESE and STER are effective and safe treatments for gastric SETs.The treatment efficacy between STER and ESE for treating gastric fundus SETs was comparable,and a large-scale,randomized study is necessary for a more confirmed conclusion.