Cancer is a disease marked by the uncontrolled growth of abnormal cells.
The abnormal cells may no longer do the work of normal cells, and they crowd out and destroy healthy tissue. Lung cancer is the most common cancer cause of death among men and ranks second among women. It is the second most commonly occurring cancer among men, and the third most commonly occurring cancer among women. An estimated 142,000 Americans were expected to die due to lung cancer in 1990. Lung cancer may also be the most tragic cancer because, in most cases, it might have been prevented.