Neoadjuvant Chemoimmunotherapy or Chemoradiotherapy in ESCC

Inclusion Criteria: * Be able to understand and voluntarily provide written informed consent before any procedures required for the study are performed. * Age between 18 and 75 years. * Eastern Cooperative Oncology Group (ECOG) performance status score 0-1. * Histologically confirmed esophageal squamous cell carcinoma. * T1N1-3M0 or T2-4aNanyM0 as determined by endoscopic ultrasound (EUS) or magnetic resonance imaging (MRI) and PET/CT. All lesions, including tumor and lymph nodes, were required to be resectable. * Tumors with strong FAPI uptake on baseline PET/CT scan should have a maximum standardized uptake value (SUVmax) ≥5.0. * Subjects were required to provide preoperative paraffin blocks or white slides of tumor tissue, or freshly collected samples, including at least 3 unstained FFPE pathological slides. * Female subjects of childbearing potential must have a urine or serum pregnancy test with a negative result within 3 days before the first dose. If urine testing could not confirm the negative result, serum testing was required. Participants who had sex with an unsterilized male partner were required to use an effective contraceptive method from the time of screening and to agree to continue using a contraceptive method for 120 days after the last dose. Discontinuation of contraception after 120 days was discussed with the investigator. * Unsterilized male subjects who have sex with a female partner of childbearing potential are required to use effective contraception from the time of screening until 120 days after the last dose; Discontinuation of contraception after 120 days is also discussed with the investigator. * Laboratory tests must meet the following criteria: Absolute neutrophil count (ANC) ≥ 1500 /µL Platelet count ≥ 100,000/µL Total bilirubin ≤ 2.5 times the upper limit of normal Creatinine clearance (calculated by the following formula) ≥ 60 mL/ minute AST/ALT ≤ 1.5 times the upper limit of normal The modified Cockcroft-Gault equation was used to estimate creatinine clearance (Clcr) : \*\* For serum creatinine concentration (Sr Cr) expressed in mg/dL: Clcr (mL/min) = (140-age) × actual weight (kg)/(72 × Sr Cr(mg/dL)) Results for women were calculated using 85% of the Clcr values for men. Exclusion Criteria: * A history of malignant tumors within the past five years prior to registration (excluding basal cell carcinoma, squamous cell skin cancer, carcinoma in situ of the bladder, or cervical cancer). Patients who have undergone surgical treatment and have remained disease-free for over five years are still eligible for inclusion. * Known contraindications include severe allergic reactions to taxanes, platinum-based drugs, 5-FU medications, etc. * Patients with a documented history of severe allergic reactions to sintilimab. * Patients who are unwilling or unable to adhere to visit schedules, treatment plans, laboratory tests, and other study requirements. * Previous radiotherapy administered to the chest or abdomen. * Patients who have received treatments involving platinum agents, taxanes, 5-FU drugs or PD-1 inhibitors. * T4 stage tumors exhibiting definite invasion into the spine, heart, major blood vessels or tracheobronchial tree. * Patients with confirmed cervical or supraclavicular lymph node metastasis or other metastatic lymph nodes that cannot be included in the radiotherapy field nor removed during esophagectomy. * Patients diagnosed with distant metastases through PET/CT scans or other examinations indicating liver, lung or bone metastases. * Individuals suffering from significant uncontrolled cardiovascular diseases (such as heart failure), severe coronary artery disease or recent myocardial infarction; also includes those with serious conditions affecting liver or kidney function (e.g., renal insufficiency or liver cirrhosis). * History of severe central nervous system disorders or mental health issues that may impact treatment compliance and study monitoring. * Individuals presenting severe surgical contraindications that render them unable to tolerate surgery.