Efficacy Analysis of Neoadjuvant Treatment in Lung Cancer Using Low-dose Nivolumab Combined With Chemotherapy

Inclusion Criteria:

* Able to provide a signed Informed Consent Form (ICF), indicating agreement to comply with the requirements and restrictions in the ICF and protocol.
* Male or female, aged 18 years or older.
* Diagnosed with non-small cell lung cancer (NSCLC) with clinical staging IB, II, or IIIA.
* Receiving treatment at Hospital de Base.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at enrollment, with no decline from two weeks prior to the baseline period or the day of the first dose.
* Tumor sample meets the following requirements:
* Negative for EGFR gene expression.
* Negative for ALK and ROS1 protein expression.
* PD-L1 protein expression documented and assessable.
* Tumor is considered resectable upon initial assessment by three thoracic oncology surgeons (IR, CM, and HN) following a multidisciplinary review.
* Adequate organ and bone marrow function as defined below:
* Hemoglobin: ≥ 9.0 g/dL\*
* Absolute neutrophil count: ≥ 1.5 × 10\^9 /L\*
* Platelet count: ≥ 100 × 10\^9 /L\*
* \*Note: Granulocyte colony-stimulating factor (G-CSF), platelet transfusions, and blood transfusions are not permitted to meet these values.
* Serum bilirubin: ≤ 1.5 × upper limit of normal (ULN), except for participants with confirmed Gilbert syndrome, who may be included upon physician consultation.
* ALT and AST: ≤ 2.5 × ULN.
* Creatinine clearance: ≥ 50 mL/min (calculated using the Cockcroft and Gault formula).
* Life expectancy greater than six months prior to randomization.

Exclusion Criteria:

* Refusal to sign the Informed Consent Form (ICF).
* NSCLC clinical stages IA, IIIB N3, IIIC, IVA, and IVB.
* Tumors with T4 invasion of the aorta, esophagus, and/or heart; or presence of bulky N2 disease.
* Tumor deemed unresectable.
* Prior systemic anticancer therapy for NSCLC, including chemotherapy, biologic therapy, immunotherapy, or any investigational drugs.
* History of another primary malignancy, with exceptions for:
* Malignancies treated with curative intent and no active disease for ≥ 2 years before the first dose of investigational product (IP) and with a low risk of recurrence.
* Adequately treated non-melanoma skin cancer or lentigo maligna with no evidence of disease.
* Adequately treated carcinoma in situ with no evidence of disease.
* Incomplete basic medical information in the electronic medical record.
* Positive for EGFR gene expression.
* Positive for ALK protein expression.
* No available data on PD-L1 protein expression.
* Positive for ROS1 protein expression.
* Pregnant or breastfeeding at the time of enrollment.