Lung cancer is a disease in which the cells of lung tissues grow uncontrollably and form tumors. Lung cancer is the leading cause of cancer death in both men and women. It occurs most commonly between the ages of 45 and 70.
There are two kinds of lung cancer, primary and secondary. Primary lung cancer starts in the lungs. Secondary lung cancer starts somewhere else in the body; cancer cells then spread to the lungs which is referred to as Metastasis.