Lung cancer
Lung cancer is a disease caused by the rapid growth and division of cells that make up the lungs. Lung cancer is sometimes called "bronchogenic cancer", or it may be described by its particular histologic type, that is the type of tissue that is diseased. Under normal circumstances, lung cells reproduce in an orderly fashion to maintain tissue health and to repair injuries. However, when growth control is lost and cells divide too much and too fast, a cellular mass - or tumor - is formed. If the tumor is confined to a few cell layers (for example, surface cells) and it does not invade surrounding tissues or organs, it is considered benign. By contrast, if the tumor spreads to surrounding tissues or organs, it is considered malignant, or cancerous. If cancerous cells break away from the original tumor, travel, and grow within other body parts- such as the brain, bone, liver, adrenal glands, the opposite lung, or lymph nodes of the chest or collarbone (clavicle) regions - the process is known as metastasis.
