Submucosal Tunneling Endoscopic Resection For Esophageal Submucosal Tumor:A Multicenter Study

Background:Submucosal tumor(SMT)is a rare esophageal disease,accounting for only<1.0%of esophageal tumors.Esophageal SMT is a kind of subepitlhelial neoplasm.which usually does not cause clinical symptoms.The clinical detection rate is relatively low.Esophageal SMTs are mostly benign tunors and most pathological types are leiomyoma.However,there are still a few cases of gastrointestinal stromal tumors,which have malignant potential and may possess the biological characteristics of malignant tumors.Therefore,it is very important to achieve a complete resection for the obtaining of pathological diagnosis.Previously,surgical resection used to be the main treatment for esophageal SMT,but its defects included larger tissue trauma,more complications and the slower recovery of the patients;furthermore,it is often difficult to identify SMT protruding into the lumen without the assistance of a gastroscope during the procedure.With the rapid development of endoscopic technique,the detection rate of esophageal SMT has been continuously improved.Meanwhile,endoscopic techniques,such as endoscopic submucosal dissection(ESD)and endoscopic full-thickness resection(EFTR),have promoted the development of endoscopic treatment of esophageal SMT.However,although many endoscopic treatments can successfully remove submucosal esophageal tumors,the defect is that for esophageal SMT derived from the muscularis propria layer,ESD,EFTR and other methods need full-thickness resection,which is very easy to cause perforation and has a high incidence of complications.Tunnel Endoscopy(TE)is a new technique improved on ESD.Peroral endoscopic myotomy(POEM)is a xwidely-used tunnelino technique first reported by fnoue.Subsequently,on the basis of ESD and POEM,professor Xu first reported submucosal tunneling endoscopic resection(STER)and applied it to submucosal tumors originating from the muscularis propria of'the upper gastrointestinal tract.Aftenrwards,many domestic and foreign centers also began to conduct research on STER technology for the treatment of esophageal SlxMT.Aims:The purpose of this study was to evaluate the safety and efficacy of STER tor the treatment of esophagueal SMT.Methods:This studv was a retrospective,multicenter clinical trial.This stLud}y conducted a retrospective analysis of the data of 148 lesions from 144 patients with SMT originating from the muscularis propria layer,xwho underwent STER between September 2011 and December 2018.Among them.19 cases were treated with modified STER,which xwas called open submucosal tunneling endoscopic resection(O-STER).Before the operation,all patients were identified to have esophageal SMT by endoscopy and the nature and origin of the tumor were evaluated bv endoscopic ultrasonography and chest CT.EventLually,the patient xwas diagnosed with a esophageal SMT,which originated from the muscularis propria and protruded into the lumen.and no evidence of malignant tuimor was found.During follow-up period,all patients were fiollowed Lup by gastroscopy or ultrasonography to dc(etermine whether tunmor residues or recurrence occlurred.The baseline characteristics,clinical outcomes,pathological diagnosis and f'ollow-up data of all patients were statistically analyzed to evaluate the safety and efficacy of STER in the treatment of esophageal SMTs.Results:A total of 144 patients were included in this studv,and 148 tumors were resected.The mean age of the patients was 48.6years.Most of the tumors were primarily located in the:middle and lower esophagus.The mean size of the tumors was 20.5±10.4mm(range 8-60 nm).All of the tumors originated from the muscularis propria(MP)of the esophagus,and there were 105(70.9%)cases located in the superficial MP layer,and 43(29.1%)cases originating from the deep MP layer.The mean operation duration was 46.8±24.9 min(range 10-150min).The total en bloc resection rate and the complete resection rate were 98.0%and 100%,respectively.Regarding complications,there were 9(6.3%)cases of perforation during the operation,2(1.4%)cases of pneumothorax,and 7(4.9%)cases of simple subcutaneous emphysema in the neck and chest area.In O-STER group,the mean size of tumors was 32.2±12.2mm;and the mean operation time was 58.9±23.0min,while the complete resection rate and the en bloc resection rate were 100%,and no complications or recurrence occurred.Postoperative pathological diagnosis confirmed that 139(93.9%)cases were leiomyoma,8(5.4%)cases were gastrointestinal stromal tumor,and 1(0.7%)case was granular cell tumor.The mean duration of hospitalization was 6.0±2.7 days.During a 16.5-month follow-up period,no tumor recurrence or distant metastasis occurred,and no delayed perforation,bleeding,gastrointestinal leakage or other serious complications occurred.Conclusions:STER is a safe,effective and minimally invasive technique for treating esophageal SMT originating from the muscularis propria layer,with the advalntages of fewer complications and higher complete resection rate.