SOX regimen, consisting of oral S-1 and intravenous oxaliplatin, is the preferred regimen for perioperative chemotherapy for gastric cancer. The goal of this clinical trial is to compare the efficacy and safety between S-1 combined with oxaliplatin by arterial infusion, as neoadjuvant chemotherapy, and conventional SOX regimen, in locally advanced gastric cancer. The main question it aims to answer is: whether arterially infused oxaliplatin plus S-1 has the potential to be a better neoadjuvant option for patients with locally advanced gastric cancer.
Participants will be randomised, and receive:
* 3 cycles of conventional SOX chemotherapy plus PD-1 antibody or arterial infused oxaliplatin plus S-1 and PD-1 antibody, as neoadjuvant chemotherapy; * Adequate gastric resection along with D2 lymph node dissection; * 3 cycles adjuvant chemotherapy using SOX regimen plus PD-1 antibody. * Administration of S-1 regularly till 1 year after surgery.
Researchers will compare Major pathological response rate (MPR) ，pathologic complete response rate（pCR）,the 2-year overall survival (OS) rates, 2-year disease free survival (DFS), R0 resection rates, and adverse events, to see if the modified perioperative chemotherapy improve the prognosis of patients with locally advanced gastric cancer.
Eastern Cooperative Oncology Group(ECOG) score 0-1
Ambulatory males or females, aged 18-75 years
Histologically or cytologically confirmed adenocarcinoma of the stomach or gastroesophageal junction (Siewert type II or III)
Locally advanced gastric carcinoma (cT3N2-3M0, cT4aN1-3M0, cT4bNanyM0, American Joint Committee on Cancer (AJCC) TNM staging system 8th edition)
Patients can not bear surgical procedure.
Pregnant or lactating women.
HER2 overexpression(+++) confirmed by immunohistochemistry.
Previous cytotoxic chemotherapy, radiotherapy or immunotherapy.