Septum-guided Segmentectomy for 2-3 cm Clinical Stage IA3 Peripheral Non-Small Cell Lung Cancer

This is a single-center, prospective, single-arm, open-label clinical trial evaluating the efficacy and safety of septum-guided segmentectomy in patients with 2-3 cm clinical stage IA3 peripheral non-small cell lung cancer (NSCLC) with a consolidation-to-tumor ratio (CTR) greater than 0.5 and up to 1.0. All eligible participants will undergo planned septum-guided anatomical segmentectomy or combined segmentectomy after intraoperative frozen-section confirmation of node-negative (N0) lymph node status. The primary endpoint is 3-year recurrence-free survival (RFS).