Gastric cancer surgery is divided into radical surgery and non-radical surgery. Non-radical surgery refers to surgery for patients who cannot be cured, and can be divided into tumor-reducing surgery and palliative surgery according to the purpose of surgery. Tumor reduction surgery refers to gastrectomy for patients with non-curative factors (such as unresectable liver metastases or peritoneal metastases) and without tumor-related complications (bleeding, obstruction, perforation), and the purpose of the surgery is to reduce the tumor load. Currently, a clinical study (JCOG0705) comparing chemotherapy with tumor reduction is being performed jointly in Japan and Korea. Palliative surgery is a procedure performed in patients with non-curative factors (such as existing unresectable liver metastases or peritoneal metastases) and acute tumor-related complications (bleeding, obstruction, perforation). Palliative gastrectomy or short-circuit surgery may be performed. Some studies have reported better outcomes for gastrojejunostomy with partial or complete dissection of the open gastric body lesion compared to simple gastrojejunostomy. Radical surgery is divided into standard radical surgery and non-standard radical surgery. Standard surgery refers to resection of more than 2/3 of the stomach and D2 lymph node dissection, with at least 75 px distance between the margins of T2 or higher confined gastric cancer and at least 125 px distance between the margins of invasive gastric cancer (except for esophageal invasion), less than this distance should be examined by rapid pathological section; the number of lymph nodes dissected should be at least 16. Non-standard surgery refers to surgery that changes the extent of gastrectomy or lymph node dissection according to the extent of the lesion, including reduction surgery and expansion surgery. Reduction surgery is a procedure in which the extent of gastrectomy or lymph node dissection is less than that required for standard radical surgery. Extended surgery is a procedure in which the extent of gastrectomy or lymph node dissection exceeds the requirements of standard radical surgery.