Neoadjuvant Immunotherapy Plus Chemotherapy in Borrmann Type 4 and Large Type 3 Gastric Cancer

Who May Qualify: - diagnosed by tissue sample (biopsy-confirmed) gastric adenocarcinoma,cT1-2N+M0 or cT3-4NanyM0; - Males or females, aged 18-70 years; - Gastroscopy and abdominal computed tomography (CT) scan-confirmed typical scirrhous gastric cancer (borrmann type 4) or large type 3 (over 8 cm); - No peritoneal metastasis confirmed by laparoscopic exploration and with cytological examination of peritoneal washing of the Douglas pouch; - You should be able to carry out daily activities with 0 level of ability (ECOG 0) or 1; - Sufficient organ function: - white blood cell count \> 4\*10\^9/L, neutrophil cell count \> 1.5\*10\^9/L, hemoglobin \> 90 g/L, platelet count \> 100\*10\^9 /L - Serum bilirubin ≤ 1.5×upper limit of normal (ULN), AST, ALT ≤ 2.5×ULN - Creatinine ≤ 1.5 ×ULN or serum clearance \> 60 ml/min - INR and aPTT ≤ 1.5 × ULN, only for subjects not receiving anticoagulant therapy;Subjects undergoing coagulation therapy should use a stable dose - No prior anti-tumor therapy; - Have signed willing to sign a consent form before the beginning of treatment. Who Should NOT Join This Trial: - History of another malignancy within the last five years; - Previous cytotoxic chemotherapy, radiotherapy or immunotherapy - Unable to take drugs orally - Allergic to to any drug of the study regimen; - Women who are pregnant or breastfeeding or may be pregnant Always talk to your doctor about whether this trial is right for you.