DECAMP 1 PLUS: Prediction of Lung Cancer Using Noninvasive Biomarkers

Inclusion Criteria: * Radiologic diagnosis of solid indeterminate pulmonary nodule (0.8 to 2.5 cm) identified in the past 3 months OR semi-solid (mixed density) nodule with solid component of at least 0.6 cm identified in the past 12 months; must be of appropriate size at enrollment. * CT scan completed within 3 months prior to enrollment * Able to tolerate all biospecimen collection as required by protocol * Able to comply with standard of care follow up visits including clinical exams, diagnostic work-ups, and imaging for approximately three years from enrollment * Able to complete the Patient Lung History questionnaire with study staff Arm 1 - Screening * Age 55-77 years old * Current and former smokers with 30 pack-years or more(and quit less than 15 years ago) Arm 2 - Incidental * Age \> 45 years old * Current and former smokers with 10 pack-years or more(and quit less than 15 years ago) Exclusion Criteria: * History or previous diagnosis of primary lung cancer, metastatic lung cancer, or any other non-lung cancer within 5 years (not including non-melanoma skin cancer) * Symptoms of lung cancer (unexplained weight loss 10 lbs or more in 3 months, recent hemoptysis) * Diagnosis of pure ground glass opacities for the target lesion on chest CT within the last 12 months (i.e., mixed features on the target lesion and pure ground glass opacity on non-target lesions are acceptable as mentioned above)