Clinical Study of Low-dose Interval Radiotherapy Combined With Tirelizumab and SOX Chemotherapy Neoadjuvant Therapy for Locally Advanced Gastric/Gastroesophageal Junction Adenocarcinoma

Radiotherapy: 5×3Gy. The preoperative radiotherapy target was outlined by radiotherapy physicians according to the NCCN Guidelines for Gastric/esophagogastric Junction Tumor 2024 edition and the surgeon's opinions. The first and third cycles were 5×3Gy.

The first and third cycles are 5×3Gy radiotherapy D1 to 5, intravenous administration for tirelizumab 200 mg D6, intravenous administration for oxaliplatin 130 mg/m2 D6, and oral administration twice a day for S-1 40 mg/m2 D6 to 19. The second and fourth cycles are intravenous administration for tirelizumab 200 mg D1, intravenous administration for oxaliplatin 130 mg/m2 D1, and oral administration twice a day for S-1 40 mg/m2 D1 to 14. Every treatment cycle is spaced 1 week apart.

Surgical treatment is completed within 3-5 weeks after the end of neoadjuvant therapy.

Postoperative adjuvant therapy is 4 cycles of SOX chemotherapy.