The purpose of this registry study is to actively monitor people with GGOs and collect information about them, so that investigators can learn more about these lesions and about the risk of developing lung cancer in study participants whose GGOs are being monitored in the active surveillance program.

Inclusion Criteria:

• Age greater than 18 years
• Have two or more GGOs on initial CT imaging
• GGOs must be measure ≤3.0 cm and ≥0.6 cm in the greatest dimension
• GGOs must be greater than half ground glass

A biopsy is not necessary for inclusion in the trial. Biopsy of a GGO, even with a diagnosis of adenocarcinoma, does not necessarily preclude enrollment in this surveillance protocol. In other words, patients with a diagnosis of adenocarcinoma are still eligible, at the discretion of the clinician and/or investigator, if they meet the above criteria.

Exclusion Criteria:

• Patients who are actively undergoing lung cancer treatment or have a history of lung cancer, except for cases of completely resected pathologic stage IA nonsmall cell lung cancer (NSCLC). Patients with stage IA NSCLC and multiple GGOs can enroll in this active surveillance protocol after complete resection of the NSCLC and confirmation of stage on final pathologic assessment.
• The presence of any solid lesion ≥0.6 cm suspicious for malignancy.
• Patients who are actively undergoing treatment for other malignancies

Patients with GGOs or mixed subsolid pulmonary nodules may be recruited from participating Thoracic Oncology Surgical Group (TSOG) sites, in accordance with local institutional practice and referral patterns, and assessed for eligibility based on the criteria listed below.

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made following one year after publication and for up to 36 months later. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.