This is a study from Eastern Cooperative Thoracic Oncology Project, numbered as ECTOP-1009. Systematically mediastinal lymph node dissection or not in clinical stage T1 ground-glass dominated invasive lung adenocarcinoma: a multi-center, prospective clinical trial

Following interim analysis of 302 patients revealed no lymph node metastasis in either study arm and 100% 2-year disease-free survival in both arms. The selective non-mediastinal lymph node dissection (non-SLND) arm had reduced complications (JCO 2025; doi:10.1200/JCO-25-00610). The study design has been amended to a single-arm prospective cohort. All enrolled patients meeting inclusion criteria will sign informed consent and receive non-SLND. The primary endpoint remains 3-year disease-free survival (DFS).

The sample size has been recalibrated to 545 patients based on historical control 3-year DFS of 96.6%, a stricter non-inferiority margin of 2.5%, 90% power, and the 1-sided alpha of 2.5%.

Inclusion Criteria:

• Clinical stage T1N0M0 and planned curative surgery.
• A single lesion detected on computed tomography (CT) scan featured as ground glass nodule(GGO) and C/T ratio ≤0.5.
• Age 18 to 75.
• Patients who have signed the informed consent form.

Exclusion Criteria:

• Other than invasive adenocarcinoma by pathological analysis.
• Patients undergoing wedge resection but not meeting the specific conditions of a Consolidation/Tumor Ratio (CTR) ≤ 0.25 AND a maximum tumor diameter ≤ 2 cm, based on the oncological outcomes of the JCOG0804/WJOG4507L trial.
• Not complete resected or curative intent.
• Patients who have history of other malignant tumors.
• Patients who have history of thoracic surgery.
• Patients who have received radiation, chemotherapy or other treatments previously.

Study Protocol, Inform Consent Form, Clinical Study Report would not be shared after the study begin.

Treatment groups will be open to both patients and surgeons.