Predicting Non-small Cell Lung Cancer (NSCLC) Lymph Node Metastasis: Integrating Circulating Tumor DNA (ctDNA) Mutation/ Methylation Profiling With Positron Emission Tomography-computed Tomography (PET-CT) Scan

A highly sensitive tumor-naïve MRD panel of ctDNA will be employed to detect preoperative blood. Some patients will undergo methylation profiling to prospectively establish LNMs-specific ctDNA methylation signatures.

A certain number (depending on the Results of Stage 1) of patients requiring invasive mediastinoscopy or EBUS-TBNA, based on the clinical guidelines, will be included for blood ctDNA mutation/methylation profile (or combined PET-CT), and the detection rate of LNMs will be assessed in patients with negative preoperative blood ctDNA mutation/methylation (or combined PET-CT). The accuracy of predicting LNMs will be compared with that of patients with negative or positive preoperative blood ctDNA mutation/methylation (or combined PET-CT).

For patients with negative preoperative blood negative testing (ctDNA mutation/methylation profiles alone or in combination with PET-CT), systematic lymph node sampling/dissection and no lymph node dissection will be grouped and compared. Regular follow-up is performed to investigate the impact on long-term MRD negative duration and prognosis.