"Conservative surgery is performed for patients with early gastric cancer, according to the guideline proposed from Japanese Gastric Cancer Society.  There are many kinds of operations, such as ordinary open surgery, laparoscopic-assisted gastrectomy, laparoscopic intragastric surgery, pyrolus preserving gastrectomy, hand-assisted laparoscopic surgery.  Indications of the operations are various, but it is necessary to have standard indication for each procedure.  Standard operation for advanced gastric cancer in Japan is D2 gastrectomy.  Surgeons in Eastern world believed that D1 + alpha or D1 + adjuvant radio-chemotherapy are the standard treatments, because of high incidence of mortality and morbidity after D2 dissection.  In Japan, D4 dissection has been performed for patients with nodal involvement, and the validity of D4 dissection is now studied by two randomized trials.  Combined resection for T4 tumor is believed to be mandatory.However, the validity of pancreato-splenectomy to yield a complete clearance of No. 10 or No.  11 lymph node station is in controversial, because of high incidence of the postoperative development of pancreatic fistula, anastomotic insufficiency and abscess.  There was no prospective study to confirm the effect of omentectomy.  Patients with advanced gastric cancer showing a serosal invasion-diameter less than 2.5 cm have less risk of peritoneal recurrence.  It may be valuable to perform randomized controlled study consisting of omentum-preserving gastrectomy and gastrectomy with omentectomy.  Prognosis of patients with peritoneal dissemination was improved by intraperitoneal chomo hyporthormia and peritonectomy, and prospective studies should be done to compare the effects of systemic chemotherapy and regional chemotherapy combined with peritonectomy.  Furthermore, effects of neoadjuvant chemotherapy with cytoreduction with R0 resection should be confirmed by prospective studies."