Spatially Fractionated Radiotherapy With Tislelizumab and Chemotherapy for Bulky Stage III NSCLC: A Phase II Trial

Inclusion Criteria: * Voluntary agreement to participate and signed written informed consent. * Cytologically or histologically confirmed (via percutaneous lung biopsy, bronchoscopy, mediastinoscopy, etc.) bulky stage III non-small cell lung cancer (NSCLC) per AJCC 9th edition staging, with primary tumor \>5 cm (T3-T4), N0-N2, and no prior chemotherapy, radiotherapy, surgery, or immunotherapy. * Pulmonary lesion considered potentially resectable by a multidisciplinary team (MDT) including a thoracic surgeon. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0-1. * Adequate hematologic and organ function as demonstrated by: Absolute neutrophil count ≥ 1,500 × 10⁹/L. Platelet count ≥ 100 × 10⁹/L. Hemoglobin \> 9.0 g/dL. Serum creatinine ≤ 1.5 × upper limit of normal (ULN) or creatinine clearance (CrCl) ≥ 40 mL/min. AST/ALT ≤ 3 × ULN. Total bilirubin ≤ 1.5 × ULN. FEV1 ≥ 1.2 L or \> 40% of predicted value. INR/APTT within normal limits. -Age 18 to 75 years (inclusive). Exclusion Criteria: * Has or is suspected of having an autoimmune disease. Note: patients with vitiligo, type I diabetes mellitus, or hypothyroidism (Hashimoto's thyroiditis) requiring only hormone replacement therapy may be enrolled if no significant signs of recurrence are present. * Requires systemic corticosteroid therapy (\>10 mg prednisone or equivalent per day) or other immunosuppressive agents within 14 days after enrollment. Note: inhaled or topical corticosteroids, or adrenal hormone replacement therapy (\>10 mg prednisone or equivalent per day) for patients without active autoimmune disease, are permitted. * Prior history of thoracic radiotherapy. * Active bleeding prior to treatment. * Severe cardiac, pulmonary, hepatic, renal, or hematopoietic dysfunction, cachexia, or any condition that would preclude tolerance to radiochemotherapy. * History of diabetes mellitus for \>10 years with poorly controlled blood glucose. * History of interstitial lung disease or non-infectious pneumonitis. * NSCLC with known EGFR-sensitizing mutations, ALK fusion gene, or ROS1 rearrangement. * History of another malignancy (excluding non-melanoma skin cancer and carcinoma in situ of the bladder, stomach, colon, endometrium, cervix, melanoma, or breast) unless the malignancy has been in complete remission for ≥2 years and no additional anti-tumor therapy is required during the study period. * In the investigator's opinion, medically, psychologically, or physically unable to complete the study or to understand the patient information. * Prior treatment with anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CTLA-4, or other agents targeting T-cell co-stimulation or immune checkpoint pathways. * Active hepatitis B (HBV DNA ≥ 2000 IU/mL or ≥ 10⁴ copies/mL) or hepatitis C (anti-HCV antibody positive and HCV-RNA above the lower limit of detection). * HIV-positive or diagnosed with acquired immunodeficiency syndrome (AIDS). * Known or suspected allergy to the study drugs or to any agent used in this trial. * Pregnant or breastfeeding women.