Clinical Research Directory

Inclusion Criteria: 1. Age 18 to 80 years. 2. Solitary pulmonary nodule with whole-tumor maximal diameter \<=2 cm confirmed by preoperative thin-slice CT (\<=1 mm) and 3D reconstruction. 3. Solid-dominant nodule with consolidation-to-tumor ratio (CTR) \>0.5, including pure-solid nodules. 4. Deeply located lesion, defined as the lesion center located in the inner two-thirds of the lung field on axial, coronal, and sagittal MPR images. 5. Clinically definite suspected primary NSCLC after complete preoperative work-up and MDT discussion, with estimated malignancy probability \>=95%. Preoperative pathologic confirmation is not mandatory, but preoperative or intraoperative pathology should be obtained when technically safe and feasible. 6. Complete staging with thin-slice contrast-enhanced chest CT, whole-body PET-CT, brain contrast-enhanced MRI or CT, and serum tumor markers as appropriate; clinical stage IA (cT1a-bN0M0) without regional nodal or distant metastasis. 7. Cardiopulmonary function sufficient to tolerate both lobectomy and segmentectomy, with FEV1 and DLCO \>=60% predicted. 8. Written informed consent, including special disclosure that final pathology may be benign. 9. Centralized imaging review confirmation by the lead-center technical committee before randomization. Exclusion Criteria: 1. Lesion located in the right middle lobe. 2. Lesion located in the inner two-thirds but adjacent to the lung apex or base and judged suitable for wedge resection. 3. Two or more lesions requiring anatomic resection. One secondary lesion requiring only non-anatomic wedge resection is allowed; two main lesions in the same segment are excluded. 4. Prior ipsilateral lung surgery or another malignancy within 5 years. 5. Severe cardiovascular or cerebrovascular disease or other comorbidity making lobectomy or conversion to lobectomy intolerable. 6. Planned basal segmentectomy (S7-10); proper segmentectomy is permitted.