780. NEOADJUVANT IMMUNOTHERAPY COMBINED WITH CHEMORADIOTHERAPY VS NEOADJUVANT CHEMORADIOTHERAPY FOR LOCALLY ADVANCED ESOPHAGEAL CARCINOMA (CSTAGEII-III): A MULTI-CENTER PROSPECTIVE RANDOMIZED CLINICAL TRIAL (ICROSS)

Abstract Background The role of neoadjuvant immunotherapy combined with chemoradiation in the treatment of esophageal cancer is not yet fully understood. This study aims to compare the efficacy and safety of neoadjuvant immunotherapy combined with chemoradiation versus traditional neoadjuvant chemoradiation in treating locally advanced esophageal squamous cell carcinoma (stages cII-III). Methods This prospective randomized controlled trial included histologically confirmed patients with potentially resectable esophageal squamous cell carcinoma (stages cII-cIII). Patients were randomly assigned to two groups: the treatment group (Arm A) received BGB-A317 (200mg IV) combined with the CROSS regimen of chemotherapy and radiation, while the control group (Arm B) received only the CROSS chemotherapy and radiation regimen. All patients underwent surgery followed by a five-year follow-up. The primary endpoints included pathological complete response rate (pCR), tumor regression grades, and lymph node clearance. Results The study enrolled 67 patients (52 males, 15 females) aged between 18-75 years. Tumor locations were as follows: upper segment in 16 cases, middle segment in 45 cases, and lower segment in 6 cases. A total of 64 patients were included in the analysis. There were no significant differences between the two groups in terms of pCR rates (Arm A 41.4% vs. Arm B 30.8%, p=0.414), tumor regression grades, Surgical time (221.09 ± 37.54 minutes vs. 227.05 ± 50.28 minutes, p=0.593), Estimated blood loss (182.73 ± 337.41 ml vs. 90.47 ± 66.36 ml, p=0.109), and postoperative hospital stay (9.31 ± 4.12 days vs. 8.42 ± 1.16 days, p=0.555). However, the treatment group had significantly more lymph nodes retrieved during surgery compared to the control group (26.86 ± 7.96 vs. 20.85 ± 9.68, p=0.020). The safety profiles were similar between the groups with no significant adverse events observed. Conclusion For patients with locally advanced esophageal squamous cell carcinoma, neoadjuvant immunotherapy combined with chemoradiation is comparable in efficacy and safety to neoadjuvant chemoradiation alone and may facilitate more effective lymph node clearance. Although these preliminary results are encouraging, further long-term follow-up and larger-scale studies are needed to validate these clinical findings once the study is complete.