Adujvant CT+CRT vs Adujvant CT After D2 Resection for Locally Advanced Proximal Gastric Adenocarcinoma

Inclusion Criteria: * Voluntary Participation and Written Signature of Informed Consent. * Age 18-70, gender unlimited. * Gross pathology confirmed that the tumor center was within 1 cm to 5 cm of the EGJ line. Histopathologically diagnosed as adenocarcinoma. * No neoadjuvant therapy. * Transabdominal standard D2 radical operation was performed and R0 resection was performed. Ascites cytology was negative. * The pathological stages were IIB, IIIA, IIIB and IIIC. * There was no intraperitoneal implantation and distant metastasis. CT should be routinely performed to evaluate the tumor bed before radiotherapy. Positron emission tomography (PET-CT) could be accepted to determine whether there was residual or distant metastasis. * Physical condition score ECOG 0-1. * No history of serious heart and lung diseases, abnormal hematological examination and immunodeficiency: hemoglobin (Hb) \> 9 g/dL; white blood cell (WBC) \> 3 x 109/L; neutrophil (ANC) \> 1.5 x 109/L; platelet (Pt) \> 100 x 109/L; bilirubin \< 1.5 times the upper limit of normal value; glutathione transaminase (ALT) \& alanine transaminase (AST) = 2.5 times the upper limit of normal value; serum creatinine \< 1.5 times the normal value Upper limit. * No other systemic tumors were found. * Fertile men or women are willing to take contraceptive measures in the trial. * The daily energy intake is more than 1500 kcal. Exclusion Criteria: * Those who had a history of malignant tumors (except skin basal cell carcinoma, thyroid papillary adenocarcinoma and cervical carcinoma in situ, who survived for more than 3 years after treatment). * Patients with a history of neoadjuvant radiotherapy and chemotherapy before operation. * Study participants who participated in other clinical trials within 30 days before treatment. * Pregnancy, lactation or fertility without contraceptive measures. * Drug addiction and other adverse drug addiction, long-term alcoholism and AIDS patients. * Those with uncontrollable infections, seizures, or loss of self-awareness due to mental illness. * Those with a history of severe allergy or specific constitution. * Researchers believe that it is not appropriate to participate in this experiment.