Advanced gastric cancer has always been the focus and difficulty in the treatment of gastric cancer, and postoperative peritoneal recurrence is one of the key factors with poor prognosis. in recent years, hyperthermic intraperitoneal chemotherapy has been used in the treatment of advanced peritoneal metastases and achieved remarkable results. Existing studies have shown that postoperative hyperthermic intraperitoneal chemotherapy plays a certain role in reducing postoperative peritoneal recurrence of advanced gastric cancer. Our previous studies have shown that hyperthermic intraperitoneal chemotherapy adopted docetaxel combine oxaliplatin can also reduce the peritoneal recurrence of advanced gastric cancer. At present, there is a lack of comparison of the safety and efficacy of intraoperative and postoperative hyperthermic intraperitoneal chemotherapy. In this study, patients with advanced gastric cancer were selected by preoperative imaging, endoscopic ultrasonography and other examinations. The patients were randomly divided into group A: D1-2 radical gastrectomy plus hyperthermic intraperitoneal chemotherapy of docetaxel + oxaliplatin. Group B: D1-2 radical gastrectomy + postoperative hyperthermic intraperitoneal chemotherapy of docetaxel + oxaliplatin and group C: D1-2 radical radical gastrectomy .The three groups both proceed postoperative conventional adjuvant chemotherapy（SOX/XELOX）.The incidence of postoperative anastomotic leakage and other complications were collected, and the safety differences among the three groups were compared. The three-year overall survival (OS), disease-free survival (PFS), and disease-related mortality were evaluated and the long-term effects among the three groups were compared.

Background Advanced gastric cancer has always been the focus and difficulty in the treatment of gastric cancer. at present, gastric cancer with clinical stage of T3 / T4a / N + and without distant metastasis is defined as advanced gastric cancer. The conventional treatment is radical surgery plus postoperative or preoperative adjuvant chemotherapy. The overall median survival time is 10-12 months. After surgery-based comprehensive treatment, the 5-year survival rate of advanced gastric cancer is about 30%, and about 30-40% of recurrence is peritoneal recurrence or local recurrence. Postoperative peritoneal recurrence is one of the key factors for poor prognosis of advanced gastric cancer.

Previous peritoneal recurrence and metastasis was defined as the end stage of the disease. Since 1980s, Spratt et al found that chemotherapy combined with hyperthermia can improve the treat efficacy of peritoneal metastases. In the past 20 years, with the progress of accurate temperature control technology, hyperthermic intraperitoneal chemotherapy (HIPEC) has been gradually applied to various advanced peritoneal metastases. HIPEC refers to the accurate constant temperature, circulatory perfusion, filling the abdominal cavity and maintaining for a certain period of time to prevent and treat peritoneal implant metastasis. HIPEC contains three new concepts of precise temperature control, precise positioning and precise removal: (1) accurate temperature control: the accuracy of temperature measurement is less than ±0.1C, the accuracy of temperature control is less than ±0.5C, and the accuracy of flow rate control is less than ±5%. (2) accurate positioning: "x" abdominal cavity cross-placed perfusion tube to the subdiaphragm and pelvic floor to fill the whole abdominal cavity, leaving no treatment blind area, giving full play to the best effect of HIPEC. (3) accurate clearance: volume removal of free cancer cells, subclinical lesions and microcancerous nodules. Intraperitoneal hyperthermic perfusion chemotherapy has been used in the treatment of advanced peritoneal metastases such as gastric cancer, colorectal cancer and ovarian cancer, and achieved remarkable results. The overall prognosis of patients with peritoneal metastases has been greatly improved without increasing adverse reactions.

Research status Previous peritoneal recurrence and metastasis was defined as the end stage of the disease. Since 1980s, Spratt et al found that chemotherapy combined with hyperthermia can improve the treat efficacy of peritoneal metastases. In the past 20 years, with the progress of accurate temperature control technology, hyperthermic intraperitoneal chemotherapy (HIPEC) has been gradually applied to various advanced peritoneal metastases. HIPEC refers to the accurate constant temperature, circulatory perfusion, filling the abdominal cavity and maintaining for a certain period of time to prevent and treat peritoneal implant metastasis. HIPEC contains three new concepts of precise temperature control, precise positioning and precise removal: (1) accurate temperature control: the accuracy of temperature measurement is less than ±0.1C, the accuracy of temperature control is less than ±0.5C, and the accuracy of flow rate control is less than ±5%. (2) accurate positioning: "x" abdominal cavity cross-placed perfusion tube to the subdiaphragm and pelvic floor to fill the whole abdominal cavity, leaving no treatment blind area, giving full play to the best effect of HIPEC. (3) accurate clearance: volume removal of free cancer cells, subclinical lesions and microcancerous nodules. Intraperitoneal hyperthermic perfusion chemotherapy has been used in the treatment of advanced peritoneal metastases such as gastric cancer, colorectal cancer and ovarian cancer, and achieved remarkable results. The overall prognosis of patients with peritoneal metastases has been greatly improved without increasing adverse reactions.

A French analysis of 1125 patients over the past 25 years shows that tumor cell reduction surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy(HIPEC) may benefit patients' survival regardless of the origin of peritoneal metastatic cancer. Foreign GASTRICHIP studies have shown that radical resection of advanced gastric cancer D1-2 gastric cancer plus postoperative hyperthermic intraperitoneal chemotherapy can reduce postoperative peritoneal recurrence of advanced gastric cancer to a certain extent. At present, the HIPEC study of advanced gastric cancer in China is mainly based on the mode of surgery combined with postoperative HIPEC treatment, including the ongoing NCT02381847 study led by Professor Guan Wenxian of Nanjing Gulou Hospital and the NCT03604614 study led by Professor Wang Wei of Guangdong Hospital of traditional Chinese Medicine. both of them are aimed at the safety and efficacy of postoperativehyperthermic intraperitoneal chemotherapy for advanced gastric cancer. At present, there is no clinical study on hyperthermic intraperitoneal chemotherapy at home and abroad.

Inclusion Criteria:

• 1.Patients with gastric adenocarcinoma diagnosed pathologically from 18 to 65 years old.
• 2.Transthoracic and abdominal contrast-enhanced CT and endoscopic ultrasonography were diagnosed as cT3 / T4 N (+).
• 3.There are no obvious surgical taboos in cardiopulmonary function and blood coagulation.
• 4.Ability to provide informed consent

Exclusion Criteria:

• 1.Physical strength score ZPS > = 2.
• 2.Distant metastasis
• 3.Pregnant or lactating.
• 4.Have serious chronic diseases (hypertension, diabetes, etc.).
• 5.Allergic to chemotherapeutic drugs.
• 6.Poor compliance

Patients who was diagnosed with gastric adenocarcinoma by pathology in the first affiliated Hospital of Jiaotong University since November 2019.