Recovery Of Gastric Electrical Activity After Endoscopic Submucosal Dissection Of Gastric Stromal Tumor

Background and Objects:Gastrointestinal stromal tumor (GIST) is a common kind of gastrointestinal interstitial tissue tumors. It was found that GIST accounted for 2.2% of cancers of gastrointestinal tract, and the annual incidence rate was 1.45/ million. However, the research of autopsy and surgical specimens found that the discovery rate of GIST tumourlets (also known as minute GISTs, ICC hyperplasia, microscopic GISTs, minimal GISTs, and sclerosing stromal tumourlets) was 22.5% within the people over the age of 50. So the incidence of GIST and GIST tumourlet should be very high, but the detection rate in clinical practice remains low. At present, electronic endoscopy, endoscopic ultrasonography and imaging examinations are the mainly preoperative diagnosis methods. And final diagnosis of GIST relies on pathological changes and immunohistochemistry. Therefore, it is needed to do more research about the effective methods of early diagnosis of GIST.It's believed that GIST is originated from Cajal cell (interstitial cells of Cajal, ICC) in the gastrointestinal tract or the stem cells differentiated to ICC by most scholars. Cajal cells are distributed in reticular formation between the muscles in the gastrointestinal tract, and act as the pacemaker cells of slow-wave activity. And the slow waves are the starting potential of gastrointestinal myoelectrical activity. Otherwise, Furuzonoc in Japan found that GIST cells retain some ionic mechanisms which are the same as ICC pacemaker. So that provides a theoretical basis to look for new diagnostic methods of GIST. Electrogastrogram (EGG) can accurately measure the slow wave and is the reliable method of the diagnosis of gastric dysrhythmia. Multi-lead Electrogastrogram can record and report the gastric myoelectrical activity of different parts of stomach.Our object is to study whether GIST influences the gastric myoelectrical activity by multi-lead electrogastrogram, whether the influence has the specificity compared with the other gastrointestinal submucous tumor, and the recovery of gastric biological electrical activity after Endoscopic Submucosal Dissection (ESD)Methods:GIST and Non-GIST group (including Ectopic pancreas group and Polyp group) were distinguished by pathology and immunohistochemistry after ESD. GIST group,8 cases of male, female 6 cases, the average age was 51.93±14.39 years old, occurred in 11 cases of gastric fundus,3 cases of gastric antrum. Ectopic pancreas group had 5 cases of male, female 8 cases, the average age was 53.15±11.28 years old. Polyp group had 4 cases of male, female 6 cases, the average age was 48.80±15.83 years old. The three groups were taken exam of the multi-lead electrogastrogram before ESD, one week and one month after ESD. Some cases were followed up in 12 or 17 months after ESD. Healthy control group had 15 cases of male, female 15 cases, the average age was 50.9±11.37 years old. The average frequency (MF), percentage of normal frequency (N%), bradygastria percentage (B%), tachygastria percentage (T%), the average amplitude (MA) and the time difference were recorded and analyzed using statistical software SPSS11.5.Results:Comparison in group:It was found that fasting MF, N%, T% before ESD in GIST group had significant recovery after surgery (P<0.05),while all the postprandial parameters had no significant difference (P>0.05). Nearly all the parameters before ESD in Ectopic pancreas group and Polyp group had no significant difference (P>0.05) with those after surgery. Comparison during groups:Compared with Control group, fasting MF, N%, T%,MA and all the postprandial parameters before ESD of GIST group had significant difference (P＜0.05), while only the fasting MA had significant difference (P＜0.05) after ESD. Compared with Non-GIST group, nearly all the parameters before ESD had significant difference (P<0.05). Only individual parameters of several laeds in Ectopic pancreas group and the polyp group had significant difference (P<0.05) compared with the control group. GIST group presented more tachygastria than Non-GIST group, and even more than control group (P<0.05). Furthermore gastric fundus GIST presented more tachygastria than gastric antrum GIST. Besides, GIST group presented more disorders than Non-GIST group, and even more than control group (P<0.05).Conclusions:The existence of GIST may affect the gastric slow wave rhythm, the peak potential and spreading of slow wave:1. GIST may affect the normal fasting and postprandial reaction of stomach.2. GIST may affect normal slow wave rhythm.3. GIST should present more tachygastria, especially gastric fundus GIST. 4. The slow wave propagation may be affected by GIST, causing more disorders happened.5. Gastric biological electrical activity can be recovered after endoscopic dissection of gastric GIST.