Neoantigen Vaccines in Esophageal Squamous Cell Carcinoma

Inclusion Criteria: A. Age 18-80 years B. Locally advanced unresectable ESCC patients after radical treatment (radical chemoradiotherapy or chemoradiation); including: * Cervical esophageal segment, T4, supraclavicular lymph node metastasis, or inability/refusal to undergo surgery due to personal reasons (refer to hospital below); ② Failure of neoadjuvant or conversion therapy; ③ Postoperative local recurrence, unresectable (target lesion present). C. No evidence of tumor recurrence or metastasis 2-3 weeks after radical treatment D. Ability to provide fresh tumor tissue samples (baseline) E. Normal major organ function F. Performance status (PS) score ≤ 1 G. Patients of childbearing potential must use contraception H. Voluntary participation with signed informed consent Exclusion Criteria: A. History of fistula caused by primary tumor invasion B. High risk of gastrointestinal bleeding, esophageal fistula, or esophageal perforation C. Poor nutritional status D. Immune-related adverse events during prior radical treatment, such as Grade ≥3 pneumonitis, myocarditis, etc. E. Signs and symptoms of interstitial diseases F. Presence of any severe and/or uncontrolled medical conditions G. Presence of concurrent malignancies H. Presence of other autoimmune diseases, or prolonged use of immunosuppressants or steroids I. Difficulty in patient communication or inability to comply with long-term follow-up J. Other conditions deemed unsuitable by the investigator