The purpose of this study is to evaluate the efficacy and safety of Camrelizumab plus Concomitant Chemoradiotherapy in patients with Initial Unresectable or potentially resectable proximal Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma. 33 participants with Initial Unresectable locally advanced proximal gastric carcinoma /Gastroesophageal Junction (GEJ) Adenocarcinoma (Siewert type II/III) will be treated with conversion therapy as below once recruited:~induction chemotherapy (3w): one cycle of camrelizumab 200mg q3w and SOX regimen (oxaliplatin 130mg/m2, d1, Q3w + S-1 40-60mg bid, d1-d14,Q3w);~after the induction, concurrent Chemoradiotherapy will be started (5-6w): intensity modulated radiotherapy was given for tumors and high-risk lymphatic drainage areas, total dose:45Gy/25d, 1.8Gy/d, camrelizumab 200mg q3w, S-1 40-60mg bid, d1-d14, Q3w. The resectability assessment will be performed followed by MDT.~Participants still unresectable will receive additional conversion therapy with camrelizumab and SOX regimen. The resectability will be evaluated every 6 weeks until resectable or up to 8 cycles of conversion therapy.~Resectable patients will receive D2 resection.
This is a study of Camrelizumab in Combination With concurrent radiotherapy and SOX for Initial Unresectable or potentially resectable proximal Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma. Patients without prior palliative therapy will be treated with Camrelizumab, radiotherapy (total 45 Gy), Oxaliplatin, and S-1. The primary endpoint is the 1-year PFS rate.