Lung cancer is a disease that, like most cancers, results from uncontrolled cell growth, leading to tumor formation.  While smoking is the primary cause, there are other potential contributors, such as genetic causes and asbestos exposure. Here are five early signs of lung cancer that should not be ignored.  Breathlessness If you find yourself short of breath during activities you previously managed with ease, this could be a sign of lung cancer. Coughing Up Blood Lung cancer can cause bleeding in the airways, which may result in coughing up blood; even small traces in your phlegm can be a cause for concern.  Random Tiredness Persistent fatigue that doesn't improve with rest or feeling unusually drained after routine activities may be another potential sign of lung cancer.  Unexplained Weight Loss If you are losing weight without trying, despite no changes to your eating habits or activity levels, it could signal an underlying health issue, including lung cancer.  Appetite Loss A noticeable decrease in appetite or a significant drop in how much you feel like eating might also be an early indicator of lung cancer.