Brief Summary: RATIONALE: Screening may help doctors find lung cancer sooner, when it may be easier to treat. PURPOSE: This clinical trial is studying screening methods to see how well they find lung cancer early in current or former smokers.

Detailed Description: OBJECTIVES: * To develop a new multi-modal screening strategy and integrated methods to detect lung cancer early in current and former smokers. * To evaluate the impact of the screening modalities on the quality of life of these participants. * To develop a decision analytic framework for determining the cost and effectiveness of a novel lung cancer screening strategy in Canada. OUTLINE: This is a multicenter study. Participants undergo spirometry at baseline. Participants also undergo spiral CT scan at baseline and then at 1 and 2 years. Participants with semi-solid or solid nodules of 5-10 mm or ground glass opacity (GGO) 8-10 mm or those with growth of an existing nodule, development of a solid component in GGO, or a new nodule undergo an additional CT scan at 3 months. Some participants also undergo autofluorescence and white light bronchoscopy and bronchial biopsies. Blood samples are collected at baseline and then annually for 2 years for biomarker studies. Participants diagnosed with lung cancer undergo additional blood sample collection for biomarker studies. Participants complete questionnaires on sociodemographic factors, smoking, occupational exposure, family history, medical data, quality of life, and anxiety at baseline and then every 6 months for up to 2 years.