Lung cancer is the leading cause of cancer related death worldwide. Lobectomy or sub-lobectomy with mediastinal lymph node dissection is the standard surgery. About 50% lung nodules are pure ground-glass or part-solid nodules. Non-solid nodules rarely develop mediastinal lymph node metastasis. The present study is a prospective, multicenter and randomized clinical trial, comparing the overall survival and disease-free survival of whether performing mediastinal lymph node dissection in non-small cell lung cancer with ground-glass nodule CT features.

The study is a non-inferior statistical comparison, with 681 patients in each group. The anticipated enroll period is 3 years, followed by observation period of 5 years.

Inclusion Criteria:

• Thin-slice HRCT shows single GGN with C/T ≤ 0.5 and no lymph node metastasis;
• Clinical stage IA NSCLC (TNM 8th classification) diagnosed prior or in surgery;
• No history of malignancies within past 5 years or lung surgery;
• No anti-cancer treatment prior to surgery.

Exclusion Criteria:

• Simultaneous or metachronous (within the past 5 years) double cancers;
• Active bacterial or fungous infection;
• Interstitial pneumonitis, pulmonary fibrosis, or severe pulmonary emphysema;
• Systemic steroidal medication;
• Uncontrollable diabetes mellitus; (vi) Uncontrollable hypertension or history of severe heart disease, heart failure.

Individual participant data will be available after publication of the study.

After the follow-up period of the study.