The lungs are part of your respiratory system. When you breathe, air passes from your nose or mouth into your windpipe (trachea) and through the bronchi before entering your lungs. The most common types of lung cancer, small and non-small cell, typically start in the cells of the central bronchi.
More than 226,000 Americans will be diagnosed with lung cancer in 2012. Most will be 65 years of age or older. 85-90% of lung cancers are non-small cell.
While smoking is the primary cause of lung cancer, it can also be caused by second hand smoke, asbestos, radon gas and air pollution. Family history may be another risk factor for lung cancer. Early stage lung cancer typically does not have symptoms, but as the cancer advances, symptoms may include trouble breathing, coughing, chest pain, coughing up blood, unexpected weight loss and fatigue.