Lung cancer is the number one cancer killer in Kentucky and has a very high incidence within the 5th Congressional District of Kentucky (110.8 cases per 100,000 in period 1996-2000). Surgical removal provides the best chance for cure. Unfortunately, the majority of lung cancer cases are detected in an advanced stage, when surgical resection is impossible. This leads to shorter survival rates and increased mortality rates for lung cancer, increased patient suffering, and greater cost to the healthcare system. Methods that favor earlier detection are therefore crucial for successful treatment. One such method, low-dose spiral computed tomography (CT) is being studied to determine whether its use as a screening method will lead to earlier detection and earlier intervention, perhaps impacting survival and mortality in lung cancer. This method has a modest sensitivity to detect lung cancer, but low specificity, which leads to many false positives and a low negative predictive value. The present study is designed to address both of these limitations by: 1) identifying individuals in the population at highest risk for developing lung cancer (due to smoking habits and decreased pulmonary function) for subsequent CT screening, and 2) performing biomarker testing in conjunction with the CT scan to improve the ability to discern individuals with benign lung nodules from those with malignant tumors. The 5th Congressional District of Kentucky has one of the highest rates of lung cancer in the nation and is an ideal location to test the validity (sensitivity and specificity), feasibility (negative and positive predictive value), and efficacy (stage distribution shift to earlier stage disease, increased survival, and decreased cancer-specific mortality) of these strategies to enhance early detection.