1. Neoadjuvant chemotherapy Neoadjuvant chemotherapy is also called preoperative chemotherapy. There are increasing reports on neoadjuvant chemotherapy, which can reduce the stage, increase the surgical resection rate and improve the prognosis of patients with locally progressive gastric cancer, without increasing the surgical mortality and complication rate. At present, there is no uniform understanding of the indications, time frame of drug administration, selection of regimen and evaluation index of neoadjuvant chemotherapy for gastric cancer. For locally progressive gastric cancer without distant metastasis (T3/4, N+), neoadjuvant chemotherapy is recommended and should be applied as a two-drug or three-drug combination chemotherapy regimen, not as a single drug. ECF and its modified regimen are recommended for neoadjuvant chemotherapy of gastric cancer. The time limit of neoadjuvant chemotherapy generally does not exceed 3 months, and the efficacy should be evaluated in a timely manner and attention should be paid to judging the adverse effects to avoid additional surgical complications. Postoperative adjuvant therapy should be based on preoperative staging and the efficacy of neoadjuvant chemotherapy, with effective continuation of the original regimen or adjustment of the treatment regimen according to patient tolerance as appropriate, and replacement of the regimen for those who are not effective. 2.Postoperative adjuvant chemotherapy Postoperative adjuvant chemotherapy for gastric cancer has been widely used, so there is a consensus that adjuvant chemotherapy should be administered at the appropriate time for postoperative patients with specific stages of gastric cancer. postoperative adjuvant chemotherapy is not recommended for T1-2N0M0 patients, T2N0M0 patients with high-risk factors (such as tumor hypofractionation or high histological grade, lymphovascular infiltration, nerve infiltration or age less than 50 years old, etc.), and surgical underspecification (D0/D1 procedure), postoperative adjuvant chemotherapy should be used. All patients with negative margins (R0 resection) who are T3, T4 or lymph node positive, and all patients with microscopic residual disease at the margins (R1 resection) should receive postoperative adjuvant chemotherapy. Adjuvant chemotherapy begins when the patient’s postoperative physical status has largely returned to normal and is usually started 3-4 weeks after surgery, with combination chemotherapy completed within 6 months, and single agent chemotherapy should not exceed 1 year. The adjuvant chemotherapy regimen recommends a two-drug combination regimen of fluorouracil-based drugs combined with platinum. For those with clinicopathologic stage Ib, poor physical status, advanced age, and intolerance to two-drug combination regimens, single-agent chemotherapy with oral fluorouracil analogs is considered. Chemotherapy regimens include two-drug combination or three-drug combination regimens. Two-drug regimens include: 5-FU/LV + cisplatin (FP), capecitabine + cisplatin, tegeo + cisplatin, capecitabine + oxaliplatin (XELOX), FOLFOX, capecitabine + paclitaxel, FOLFIRI, etc. Three-drug regimens commonly used include: ECF and its derivative regimens (EOX, ECX, EOF), DCF and its modified regimens, etc. 3, intraperitoneal chemotherapy Currently, there are mainly intraperitoneal placement of fractionated drug injection, intraperitoneal lavage and hypotonic, warm chemotherapy. The purpose is to prevent and treat peritoneal metastasis. In recent years, many domestic scholars like to use warm, distilled water solution plus anti-cancer agents (5-FU, cisplatin, Paclitaxel, etc.). In case of peritoneal cancer nodules or even tiny nodules, peritoneal lavage plus transvascular drug delivery can achieve better therapeutic effect. Radiotherapy for gastric cancer includes preoperative or postoperative adjuvant treatment, palliative treatment and improvement of quality of life. The indications for postoperative radiotherapy are mainly for T3-4 or N+ (lymph node positive) gastric cancer; the indications for preoperative radiotherapy are mainly for inoperable locally advanced or progressive gastric cancer; the indications for palliative radiotherapy are local recurrence and/or distant metastasis. 5.Targeted therapy For patients with advanced gastric cancer with positive HER-2 expression (immunohistochemical staining of ++++, or immunohistochemical staining of +++ and positive FISH test), the combination of molecular targeted therapy drug trastuzumab can be considered on the basis of chemotherapy. However, it is super expensive and has limited prolongation of survival, and the best approach is to participate in clinical studies.