Submucosal Tunneling Endoscopic Resection For Upper Gastrointestinal Submucosal Tumors Originating From The Muscularis Propria Layer

Aim:To further evaluate the safety and effectiveness of submucosal tunneling endoscopic resection(STER)for upper gastrointestinal submucosal tumors(SMTs)originating from the muscularis propria(MP)layer in a larger population,and the factors that affect the effectiveness and safety of S TER in esophagus and cardia,respectively.Methods:A total of 173 patients undergoing STER with SMTs were retrospectively enrolled from May 2012 to November 2017.We finally enrolled 165 patients after exclusion of 8 ones.Clinicopathological,endoscopic,and complications data were collected and analyzed.There were three parts as following.Part I:The safety and effectiveness of STER for upper gastrointestinal SMTs was evaluated by analyzing procedure-related complications rate and effective outcomes.The outcomes in esophagus and cardia were evaluated respectively.Part II:The patients were divided into complication group and non-complication group.The differences between two groups were compared to evaluate the predictive factors of complications.Part ?:The patients were divided into en bloc resection group and piecemeal resection group.The differences between two groups were compared to evaluate the predictive factors of en bloc resection.Results:There were 53 females and 112 males.The mean size of the tumors was 22.6±13.6 mm.About 106 tumors were located in the esophagus,and 59 in the cardia.Part ?:The whole STER-related complications rate was 21.2%(35/165).The complication rates were 19.8%(21/106)and 23.7%(14/59)in esophagus and cardia,respectively.Fever(13/165),mucosal injury(12/165)and gas-related symptoms(10/165)were the most common complications.All of the complications were cured without intervention or treated conservatively.En bloc resection was achieved in 128(77.6%)patients.The margins of all en bloc resected SMTs were negative with the complete resection rate of 128(77.6%).Four SMTs were not resected completely,leading to the residual rate of 2.4%(4/165).The median operation time was 46 min(range 12-142 min).The en bloc resection rate was 81.8%(86/106)in esophageal SMTs,which was a little higher than that in cardial SMTs(42/59),indicating no significant difference(P = 0.142).Part ?:The characteristics of esophageal SMTs of the complications group(n=21)and non-complications group(n=85),were compared.Among the variables,larger size,and irregular shape were more likely to cause complications(P=0.020 and P =0.040,respectively),while age,sex and location were not the risk factors for complications related to STER for esophageal SMTs.When comparing the complications groups(n=14)with non-complications groups in cardial SMTs,irregular shape was more likely to cause complications(P=0.049),no other predictive factor was found.Part ?:When comparing the en bloc resection group(n=86)with the piecemeal resection group(n=20)in baseline characteristics of esophagus,en bloc resection was more easily achieved for smaller SMTs than for the larger ones(P=0.003)and for regular ones than irregular ones(P=0.000).The present univariate analysis showed no significant difference in age,sex,and location between the two groups.The comparison between en bloc resection group(n=42)and piecemeal resection group(n=17)on 42 patients with caridal SMTs indicated that the small and irregular shape cardial SMTs were more likely to achieve en bloc resection(P=0.009 and P=0.006),while no significant difference was found in age,sex and location.Conclusion:STER is an effective and safe methodology for upper gastrointestinal SMTs with the complication rate of 21.2%and en bloc resection rate of 77.6%.Gas-related symptoms,submucosal injury and fever were the most common complications.Although STER failed to achieve en bloc resection in about 1/4 percent of patients,piecemeal resection does not affect the long-term outcomes.The safety and effectiveness of STER in esophagus and cardia were comparable.Size and shape were predictive factors for en bloc resection in both esophagus and cardia while complications were more easily caused by larger esophageal SMTs.