Clinicopathological Features Of Small Gastric Stromal Tumors And Retrospective Study Of Endoscopic Treatment Of Gastric Stromal Tumors

BackgroundGastrointestinal stromal tumors are the most common mesenchymal tumors of the digestive tract.The functional mutation of C-KIT gene and PDGFRA gene were the main pathogenesis of GISTs.Gastric stromal tumors are the most common,accounting for 60-70%.With the popularity of endoscopy,detection rate of small gastric stromal tumors(≤2cm)was higher and higher.At present,the studies of gastric stromal tumors were mostly from the limited small-scale retrospective study,the understanding of small gastric stromal tumors was limited.Small gastric stromal tumors was one of the research hotspots in recent years.At present,the main treatment of gastric stromal tumors are surgical resection and targeted therapy,with the development of endoscopic techniques,especially endoscopic submucosal dissection(ESD),endoscopic full-thickness resection(EFTR),endoscopic submucosal tunnel dissection(ESTD)and other endoscopic new technology to carry out.Endoscopic resection of gastric stromal tumors were carried out in many endoscopic centers,but the application of endoscopic treatment of gastric stromal tumors was still controversial.ObjectiveTo explore the clinicopathological features of small gastric GISTs to improve the understanding of them and evaluate the safety and clinical efficacy of endoscopic treatment for gastric stromal tumors.MethodsThe clinical and pathological data of 106 cases of gastric stromal tumors diagnosed by pathology in Nanfang Hospital between August 2012 and December 2016 were retrospectively analyzed in the first part.The data of 86 patients with gastric stromal tumors who underwent endoscopic treatment at the Endoscopy Center of Nanfang Hospital between January 2013 and October 2016 were retrospectively analyzed in the second part.ResultsAmong the 106 patients with small gastric stromal tumors,there were 48 males and 58 females.The age of them ranged from 24 to 75 years old.The mean age was(55±10)years old.There were 84 cases(79.2%)located in the gastric fundus,13 cases(12.3%)located in the gastric body,5 cases(4.7%)located in the gastric antrum and 4 cases(3.8%)located in the cardia.The tumor size ranged from 4 to 20mm,with an average of(13 ± 4)mm.73 patients with small gastric stromal tumors showed gastrointestinal symptoms such as abdominal pain and abdominal distension,33 patients had no obvious clinical symptoms.On endoscopy,small gastric stromal tumors were spherical,round,nodular uplift submucosal tumors,which surface covered with normal mucosa.On EUS,small gastric stromal tumors originated from the muscularis propria layer,they were round or oval in shape,a few were lobulated,their boundary were clear,they showed homogeneous or uneven hypoechoic,or with hyperechoic spots,no surface ulcer formation or cystic echo area were noted.Spindle cell subtype comprised 105 cases(99.05%),mixed cell type comprised 1 case(0.95%),mitotic count ranged from 0/50HPF to 11/50HPF,92.5%(98/106)showed mitotic count<5/50HPF,7.5%(8/106)showed mitotic count>5/50HPF.CD117(106/106)and CD34(106/106)positive expression rate were 100%,DOG1(98/98)positive expression rate was 100%,SMA(25/106)positive expression rate was 23.6%,desmin(28/106)positive expression rate was 26.4%,S-100(14/106)positive expression rate was 13.2%.According to NIH risk classification,92.5%(98/106)was very low risk,6.60/%(7/106)was intermediate risk,0.9%(1/106)was high risk.Out of 86 patients with gastric stromal tumors underwent endoscopic treatment,44 patients received ESD treatment,9 patients received ESTD treatment,33 patients received EFTR treatment.61 cases were located in fundus,16 cases in gastric body,6 cases in gastric antrum,3 cases in cardia.The tumor size ranged from 4 to 49mm,the mean tumor size was(15±6.9)mm.The operation time ranged from 10 to 180 minutes,the mean operation time was(62 ± 45)minutes.83 cases(96.5%)achieved complete resection,49 cases(56.9%)occurred intraoperative perforation,which were successfully closed by endoscopic method.3 cases(3.5%)occurred intraoperative bleeding,which were handled by endoscopic method,1 patient with about 800ml of blood loss received blood transfusion after surgery,3 cases(3.5%)got infection,which were improved after anti-infection treatment,3(3.5%)patients occurred subcutaneous emphysema,3 patients(3.5%)patients occurred mild pneumoperitoneum.The gas was absorbed by conservative treatment.The mean postoperative eating time was 3.4 days(rang 2-10 days),the mean postoperative hospital stay was 5.6 days(rang 3-12 days).According to NIH risk classification,67 cases(77.9%)were very low risk,8 cases(9.8%)were low risk,9 cases(10.5%)were intermediate risk and 2 cases(2.3%)were high risk.No tumor recurrence were detected during the mean followe-up of(17.20± 10.17)months(rang 3-41 months)in 68 patients(79%).Conclusion1.Small gastric GISTs were more common in the elderly,there were no significant difference in the incidence between men and women,they were more common in the fundus,they almost showed the spindle cell subtype.Most showed very low mitotic index,the vast majority of them have low malignant potential,part of them have high malignant tendency.2.In the EUS,small gastric GISTs mostly originated from muscularis propria layer,showing uniform or uneven hypoechoic characteristics,or with hyperechoic spots,with no surface ulcer formation and cystic echo area.3.Endoscopic resection such as ESD in treatment of gastric stromal tumors was safe and had good short-term efficacy,but long-term efficacy needed further observation of more long-term follow-up study.