The concept of abdominal metastasis of gastric cancer First of all, whether it is preoperative or postoperative, as long as abdominal metastasis is clearly identified, it is the advanced stage of gastric cancer. At present, there is little chance of cure for advanced stage. It is a metastatic nodule of different sizes in the lining of the abdominal cavity (i.e. wall peritoneum), large omentum and or small intestinal lining and small intestinal wall, and in severe cases, it is fused into large lumps, accompanied by fluid accumulation in the abdominal cavity. Treatment of abdominal metastasis of gastric cancer The treatment plan is decided according to the situation of abdominal metastasis, and in the past, once abdominal metastasis appeared, surgery was no longer considered. However, recent domestic and foreign studies have shown that for patients with limited peritoneal metastasis (local peritoneal metastasis is clearly identified during laparoscopic exploration), systemic chemotherapy combined with intraperitoneal thermoperfusion chemotherapy can be considered, followed by laparoscopic exploration again. If the metastatic nodes in the abdominal wall disappear or the metastatic scar is biopsied again and no cancer cells are found in pathology, radical surgical resection of gastric cancer can be considered, and some patients have good treatment effect. However, for diffuse peritoneal metastases, that is, extensive metastases in abdominopelvic cavity, that is, there is no chance of radical surgery. For these patients, the best treatment plan at present is intraperitoneal thermoperfusion chemotherapy, and if physical conditions can be met, combined with systemic chemotherapy, and HER2 gene examination is also recommended, and if immunohistochemistry suggests (++++) or FIST examination is positive, chemotherapy combined with Herceptin targeted drug treatment is recommended. The prognosis of peritoneal metastasis of gastric cancer varies from person to person and is mainly related to the severity of metastasis, response to chemotherapy drugs and overall physical condition of the patient. Some patients can have 1-3 years of survival or even longer with peritoneal thermoperfusion chemotherapy combined with systemic chemotherapy. Intraperitoneal heat infusion chemotherapy The effect of systemic chemotherapy for gastric cancer metastasis in the abdominal cavity is limited, mainly because of the role of peritoneal-plasma barrier and the low blood concentration of peritoneal drugs. According to the difference of stability tolerance between normal cells and tumor cells, combined with the anatomical characteristics of abdominal cavity and the synergistic effect of chemotherapy and heat therapy, the warm perfusion solution (42°) mixed with chemotherapy drugs is heated to predetermined stability and perfused into the abdominal cavity with continuous heating and cyclic perfusion for 30-50 minutes, which can kill free cancer cells in the abdominal cavity and even remove tiny metastases, which is unique in the treatment of gastric cancer It has unique efficacy in the treatment of abdominal metastasis of gastric cancer.