Adebrelimab Combined With Neoadjuvant Chemotherapy in Borderline Resectable Locally Advanced Esophageal Squamous Cell Carcinoma (NEOCRTEC2501)

Inclusion Criteria:1.Voluntarily participate in the study and sign the written informed consent form.

2.Aged between 18 and 75 years old. 3.Histologically confirmed thoracic esophageal squamous cell carcinoma without distant metastasis. Patients are defined as borderline resectable after enhanced computed tomography (CT), and/or endoscopic ultrasonography (EUS), endobronchial ultrasonography (EBUS) and multidisciplinary team (MDT) discussion.

4.No prior chemotherapy or radiotherapy. 5.Estimated overall survival of no less than 3 months. 6.Eastern Cooperative Oncology Group Performance Status (ECOG PS) score of 0 or 1.

7.Hematological parameters (tested within 7 days): Hemoglobin (Hb) ≥ 90 g/L; Neutrophil count (NE) ≥ 1.5×10⁹/L; Platelet count (PLT) ≥ 100×10⁹/L.

8.Hepatic and renal function (tested within 7 days): Total bilirubin ≤ 1.5 × upper limit of normal (ULN); Creatinine ≤ 1.5 × ULN; Aspartate transaminase (AST)/Alanine transaminase (ALT) ≤ 2.5 × ULN; Alkaline phosphatase (ALP) ≤ 5.0 × ULN.

9.Absence of severe complications, including active massive gastrointestinal bleeding, perforation, jaundice, intestinal obstruction, and non-neoplastic fever above 38°C.

10.Fertile patients must adopt effective contraceptive measures throughout the study period.

11.Good treatment compliance, and able to complete follow-up assessments for efficacy and adverse events as required by the protocol.

Exclusion Criteria:

1. Patients with cervical esophageal squamous cell carcinoma.
2. Patients with distant metastasis.
3. Patients with nearly complete esophageal obstruction confirmed by endoscopy who require interventional therapy for decompression.
4. Patients with prior placement of esophageal or tracheal stents.
5. Patients with high risk of bleeding or perforation due to obvious tumor invasion into adjacent vital organs (major arteries or trachea), or patients with existing fistula formation.
6. Patients with other concurrent primary malignancies (except cured basal cell carcinoma of the skin and carcinoma in situ of the cervix).
7. Use of immunosuppressive drugs within 1 week prior to enrollment. This exclusion does not apply to intranasal, inhaled or other topical glucocorticoids, systemic glucocorticoids at physiological doses (i.e., prednisone ≤ 10 mg/day or equivalent), or glucocorticoids administered for contrast medium allergy prophylaxis.
8. Active autoimmune diseases requiring symptomatic treatment, or a medical history of such diseases within the past 2 years.
9. Known history of primary immunodeficiency.
10. Confirmed active tuberculosis.
11. History of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation.
12. Interstitial lung disease requiring corticosteroid therapy. 13Known allergy to any monoclonal antibody, chemotherapeutic agents (taxanes, carboplatin), or their excipients.

14.Severe cardiac diseases, including documented congestive heart failure, uncontrolled high-risk arrhythmia, medically treated angina pectoris, clinically significant valvular heart disease, history of severe myocardial infarction, and refractory hypertension.

15.Chronic diarrhea (≥4 watery stools per day) or renal insufficiency. 16.Active infection or active communicable diseases. 17.Neurological or psychiatric disorders impairing cognitive function. 18.Pregnant or breastfeeding women. 19.Other acute or chronic diseases, psychiatric disorders or abnormal laboratory findings that, in the investigator's judgment, may increase risks related to study participation or study drug administration, or interfere with the interpretation of study results.