A Study on Immunotherapy Combined With Radiotherapy for Esophagogastric Junction/Gastric Adenocarcinoma

"* PD-1/CTLA-4 combination antibody: Iparomlimab and Tuvonralimab， 5mg/kg on day 1, day 22, and day 43, administered via intravenous infusion, for a total of three cycles before surgery and maintained for up to 1 year after surgery.~* Radiotherapy: To be conducted within one week of the start of immunotherapy, with a total dose of DT: 30Gy, 2.5Gy × 12 fractions, once daily, five times per week. The preoperative radiotherapy target area will be delineated by the radiation oncologist in accordance with the NCCN Guidelines for Gastric/Esophagogastric Junction Cancers 2022 and in consultation with the opinions of the general surgeon.~* Surgery: Surgical treatment will be completed within 3-5 weeks after the completion of neoadjuvant therapy.~* Adjuvant therapy: Postoperative immunotherapy will be maintained for up to 1 year."