Exploratory Clinical Study of Camrelizumab Combined With Concurrent Chemoradiotherapy as an Organ-preserving Strategy for Locally Advanced Resectable Esophageal Squamous Cell Carcinoma

This study is a prospective, exploratory clinical study aimed at evaluating the feasibility and safety of camrelizumab combined with synchronous chemoradiotherapy as an organ-preserving strategy for locally advanced resectable esophageal squamous cell carcinoma. The study targets patients with locally advanced resectable stage II/III/IVa (cT1b-4aN0-3M0) ESCC. A total of 164 subjects are expected to be enrolled. The study is a randomized, non-controlled, open-label trial. Subjects meeting the inclusion criteria will be randomly assigned in a 1:1 ratio to receive either camrelizumab combined with radiotherapy, albumin-bound paclitaxel, and carboplatin treatment (Cohort 1) or camrelizumab combined with radiotherapy and capecitabine treatment (Cohort 2). The screening period for the study is 28 days. After completing screening examinations and assessments, eligible subjects will be randomly assigned to the following treatment regimens. Cohort 1: * Camrelizumab: 200 mg on Day 1, every 3 weeks * Radiotherapy: 50-50.4 Gy / 25-28 fractions, Days 1-5, once a week * Albumin-bound paclitaxel: IV infusion, 60-80 mg/m², Day 1, weekly * Carboplatin: IV infusion, AUC=1-1.5, Day 1, weekly Each cycle lasts 3 weeks, with 2-4 cycles of medication. Efficacy evaluation (imaging and endoscopic examination) will be conducted within 6 weeks after the completion of treatment. If the efficacy evaluation indicates cCR, subjects will enter Group A1 and receive camrelizumab maintenance therapy (maximum 1 year). If the efficacy evaluation does not reach cCR, after consultation between the investigator and the subject, they will enter Group B1 to undergo radical surgery, followed by camrelizumab monotherapy maintenance treatment (maximum 1 year). Cohort 2: Camrelizumab: ivgtt, 200 mg, D1, Q3W Radiotherapy: 50-50.4 Gy / 25-28 fractions, D1-D5, QW Capecitabine: p.o. 625 mg/m², BID, D1-D14, Q3W; One cycle lasts 3 weeks, with 2-4 cycles of medication. Efficacy evaluation (imaging and endosco