Watch and Wait for NeoAdjuvant Concurrent Radiochemotherapy Combined With Camrelizumab in Patients With Resectable Esophageal Squamous Cell Carcinoma，A Prospective, Single-Center, Open Label，Phase II Cohort Study （WATCHER）
To observe the 1-year disease-free survival rate （1-year PFS） of patients with resectable esophageal squamous cell carcinoma who received neoadjuvant chemoradiotherapy combined with camrelizumab and achieved clinical complete remission with watchful waiting strategy.
• Sign the informed consent. Participants signed and dated written informed consent. Informed consent must be signed prior to any protocol-related procedures that are not part of the participant's routine medical care； Participants must be willing and able to comply with scheduled visits, treatment regimens, and laboratory tests；
• Participant type and target disease characteristics Eastern Collaboration Group (ECOG) physical status score 0-1； Histologically confirmed esophageal cancer with lesions located in the thoracic esophagus, AJCC/UICC esophageal cancer staging (eighth edition) clinical stage cT2-4aNanyM0, or cT1-3N+M0； Presence of measurable lesions according to RECIST criteria； Participants must have tumor tissue samples available for PD-L1 IHC testing； No major associated pathological conditions that increase the risk of surgery to unacceptable levels. Such as: esophageal perforation and active esophageal bleeding, obvious trachea, thoracic large blood vessel invasion； According to the surgeon's assessment, the total lung function can withstand the proposed esophageal cancer resection；
• Age and reproductive status Age ≥18 years old and ≤75 years old； Females of childbearing potential (WOCBP) must have a negative serum or urine pregnancy test (minimum sensitivity of 25 IU/L or equivalent for HCG) within 24 hours prior to initiation of study treatment； Women must be non-nursing；