This study evaluates the addition of adjuvant chemoradiotherapy to adjuvant chemotherapy in the treatment of locally advanced proximal gastric adenocarcinoma after standard D2 radical resection.

Because of its special anatomical structure, local recurrence rate of locally advanced proximal gastric adenocarcinoma is still high after radical operation.

As a local/regional therapy, radiotherapy combined with concurrent chemotherapy can kill local residual tumor cells and reduce the risk of local and regional recurrence.

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.