Lung cancer is asymptomatic in its early stages. People call lung cancer the silent killer, and there are several truths. The so-called lung cancer is a mutation of the tissue cells in your own lungs. They no longer obey the body’s own orders, but grow wildly. When the cancer cells invade and destroy the surrounding tissues, resulting in their dysfunction, symptoms can be produced at this time. For example, cough, chest pain, hemoptysis, difficulty in breathing, fever caused by obstructive pneumonia, etc. For early detection, screening with low-dose CT chest scan for high-risk groups (smoking, advanced age and family history of tumor) can detect early lung cancer and remove it surgically before it spreads.