This study is a single-arm, multi-center, phase III trial conducted under the Eastern Cooperative Thoracic Oncoloy Project (ECTOP) with the identification number ECTOP-1021. The primary objective of the study is to assess the overall survival of patients with multifocal ground-glass opacities by employing a active surveillance approach rather than opting for surgical resection.

The trial aims to confirm the hypotheses that delaying surgery until GGO nodules exhibit progression or meet certain criteria offers a prognosis equivalent to those undergoing immediate surgical resection, potentially allowing many of these patients to avoid surgery altogether.

Inclusion criteria Patients eligible for enrollment in the study are required to meet all the following criteria.

1. Demonstrates the following on thin-section computed tomography (TSCT) scan:

   1. Presence of three or more GGNs (bilateral lesions are permitted).
   2. All lesions have remained stable without regression or enlargement for at least 3 months.
   3. The dominant lesion (the lesion with the largest maximum tumor diameter) has a maximum tumor diameter >=0.6cm and <=2cm.
   4. CTR <=0.25 in all lesions.
   5. No lymph node with a diameter >1cm in the mediastinal view.
   6. Not adjacent to the pleura in dominant lesion and no sign of pleural retraction in any lesions.

2. Aged 18-75 years.

3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

4. Has not previously undergo any anti-tumor drug or radiation therapy.

5. Written informed consent.

Exclusion criteria Patients will be excluded if they meet any of the following criteria.

1. History of any prior malignancies within the past 5 years.
2. History of lung surgery.
3. History of interstitial pneumonia, pulmonary fibrosis or other severe pulmonary diseases.
4. Presence of severe or uncontrolled diseases that may possibly reduce the 10-year life expectancy.

Outpatients who are willing to particiapte in the study and meet the inclusion and exculsion criteria.

The clinical data including patient characteristics and CT images.

Within five years from the study end.

Medical oncologists and surgeons who are interested in the study. Emails could be sent to the address below to obtain the shared data:

hqchen1@yahoo.com