This study is a prospective, single-arm, phase II clinical study. Screening patients with stage III GC/GEJ adenocarcinoma after D2 or broader radical resection. After enrolling in the study, the subjects receive Sintilimab combined with oxaliplatin+Tegafur, Gimeracil and Oteracil Potassium Capsules (SOX) or oxaliplatin+Capecitabine (XELOX) , in which the combined chemotherapy is up to 8 cycles, and the total course of treatment was 16 cycles. The following-up of subjects includes adverse events、disease status、living conditions and the quality of life.
Age ≥18.
Patients with histopathological confirmed gastric/GEJ adenocarcinoma.
The pTNM is confirmed between IIIA-IIIC and the PD-L1 CPS>=1.
Patients treated with D2 surgery.
Patients who had received neoadjuvent treatments before surgery.
Patients who have discovered tumor relapse or metastasis before adjuvent treatment.
Patients who have other malignant tumors.
Patients who could not swallow the tablets and capsules.