Smoking - adverse effects, Age Factors, Early Detection of Cancer - methods, Occupational Exposure - adverse effects, Humans, Risk Factors, Primary Health Care - organization & administration, Tomography, X-Ray Computed, Radiation Dosage, Lung Neoplasms - epidemiology, Tobacco Smoke Pollution - adverse effects, Lung Neoplasms - etiology, Lung Neoplasms - dia...