Individualized Tumor-Informed CtDNA Analysis for Monitoring Postoperative Recurrence in ESCC (NEOCRTEC2401)

Inclusion Criteria: 1. Operable locally advanced esophageal squamous cell carcinoma; 2. Have received neoadjuvant chemoradiotherapy ± immunotherapy and have not achieved pCR after R0 resection; 3. Can tolerate postoperative adjuvant immunotherapy; 4. Sufficient baseline tumor tissue and blood samples available for NGS testing; 5. Eastern Cooperative Oncology Group (ECOG) performance status score of 0-1; 6. Consents to and is capable of complying with the scheduled study visits, treatment plans, laboratory tests, and other study procedures 7. Expected postoperative survival time of ≥ 6 months. Exclusion Criteria: 1. Concurrent other malignant tumors; 2. Lack of a detailed histopathological diagnostic report for determining the nature of the lesion; 3. Severe and/or poorly controlled medical conditions that, in the investigator's judgment, could affect participation or interfere with study results; 4. Any social/psychological issues that, in the investigator's judgment, make the patient unsuitable for participation; 5. Unable to undergo long-term, regular postoperative follow-up at the current medical institution; 6. Unwilling or unable to comply with the study protocol.