In recent years, with the continuous advancement of endoscopic techniques and instruments, endoscopic submucosal dissection (ESD) for superficial lesions of the GI mucosa can often achieve treatment results similar to those of surgery, and has the advantages of being minimally invasive, not altering the structure of the GI tract, avoiding the risks of surgery, and reducing postoperative quality of life, etc. ESD is an economical, safe, and reliable method of treating superficial lesions of the GI tract. ESD is an economical, safe and reliable treatment for superficial lesions of the GI tract. Advantages and indications of ESD treatment The advantage of ESD treatment is that it can completely remove tumor tissue without surgery, but the limitation is that lymph node dissection cannot be performed at the same time, so there are strict indications. The current indications for ESD include differentiated adenocarcinoma without ulceration confined to the mucosal layer, differentiated adenocarcinoma with ulceration confined to the mucosal layer but less than 3 cm in extent, and differentiated adenocarcinoma with superficial submucosal layer (SM1) less than 3 cm in extent. Efficacy High block resection rate (92%-97%) and complete resection rate (73.6%-94.7%) can be achieved for early gastric cancer, with 5-year overall survival rate and 5-year disease survival rate of 96.2%-97.1% and 100%, respectively. The 5-year survival rates for esophageal ESD were 100% and 85% for those with lesions confined to the epithelium or mucosal lamina propria and those with lesions infiltrating deeper than the mucosal lamina propria, respectively. The rates of complete resection and curative resection for colorectal ESD were 82.8% and 75.5%, respectively. Risk assessment The main risks of ESD treatment include bleeding, perforation, and pain. Bleeding is the most common complication, with intraoperative bleeding being more common. In the stomach, for example, the investigators found that intraoperative bleeding in ESD is more common in the upper third of the stomach; delayed bleeding often occurs 0-30 days after surgery with vomiting of blood or black stools, mainly related to the size and location of the lesion. The rate of gastric ESD perforation is 1.2% to 9.7%, even in technically mature treatment centers, the perforation rate is about 4%, and the perforation can be closed by metal clips. the bleeding rate after ESD is 0.6% to 15.6%. The perforation rate of esophageal ESD is 0%-6%, the postoperative bleeding rate is almost 0%, and the local recurrence rate is between 0.9% and 1.2%. Colorectal ESD had a perforation rate of 4.7%, a postoperative bleeding rate of 1.5%, and a local recurrence rate of 1.2%. The occurrence of ESD complications is related to the patient’s condition, the operator’s technique and experience, and the condition of the equipment and instruments. Advanced age, abnormal coagulation, immunosuppression, severely impaired liver and kidney function, and other cardiopulmonary comorbidities will increase the risk of ESD. Postoperative management Prevention and treatment of complications The first 24 hours after the operation is the most likely time for complications to occur, so symptoms and signs should be closely observed. If there is unexplained chest or abdominal pain, chest and abdominal fluoroscopy, ultrasound or CT examination should be performed promptly; if traumatic bleeding is suspected, early endoscopic intervention is recommended to find the bleeding site and stop the bleeding. In case of intraoperative complications of perforation, gas and liquid in the digestive cavity should be aspirated, and the perforation should be closed endoscopically in time; postoperative gastrointestinal decompression, fasting and anti-inflammatory treatment should be given, and chest and abdominal signs should be closely observed; in case of ineffective conservative treatment (increase in body temperature, increase in abdominal pain, etc.), surgical treatment should be given immediately (laparoscopic exploration is recommended to repair the perforation if available). The application of postoperative antibiotics and hemostatic agents after ESD aims to prevent mediastinal, retroperitoneal or free peritoneal infections around the surgical wound and possible postoperative systemic infections, especially in those with large surgical extent, long operation time, repeated submucosal injections resulting in surrounding inflammatory edema, or possible complications of gastrointestinal perforation. Preoperative evaluation should be performed for those with large ESD scope, long operation time, and possible GI perforation, especially for colorectal lesions, and prophylactic antibiotics may be considered. Postoperative follow-up Patients with precancerous lesions should be examined by endoscopy once in the first and second year after ESD, and then followed up once every 3 years. For patients with early cancer ESD, regular endoscopic follow-up is performed at 3, 6 and 12 months after surgery, together with tumor index and imaging examination; those without residual or recurrence are followed up once a year after surgery; those with residual or recurrence continue to undergo endoscopic treatment or additional surgical resection as appropriate, and are followed up once every 3 months, and once a year after complete clearance of lesions.