LEGACY: Lung Cancer Screening in Individuals With a Lung Cancer Family History-Protocol A

Inclusion Criteria: * Age: Must meet both the upper and lower age limit criteria. * Upper age limit: ≤80 years of age * Lower age limit: * ≥40 years of age OR * ≥18 years of age AND ≤10 years of youngest relative's age at time of lung cancer diagnosis (e.g., if a relative was diagnosed at 35 years of age, participant can enroll at ≥25 years of age) * Positive family history of lung cancer (defined as): * Has ≥1 first-degree relative, OR * Has ≥2 second-degree relatives with a diagnosis of non-small cell lung cancer or small cell lung cancer (NB: a first-degree relative = parent, sibling, or child, a second-degree relative = grandparent, blood-related aunt or uncle, grandchild, blood-related niece or nephew, half-sibling) Exclusion Criteria: * Must not have a personal history of lung cancer at the time of enrollment. * Must not have a personal history of stage IV cancer of any type at the time of enrollment. * Must not have had surgical removal of any portion of the lung, excluding needle or core lung biopsy at the time of enrollment. * Must not have had a chest CT within 12 months prior to trial enrollment.