Definition

Lung cancer is a disease in which the cells of lung tissues grow uncontrollably and form tumors. A tumor is a mass or lump of tissue made of abnormal cells.

Description

Lung cancer is the leading cause of death from cancer among both men and women in the United States. Experts estimate that 28 percent of all cancer deaths—about 160,000—are caused by lung cancer. It is further estimated that at least 172,000 new cases of lung cancer are diagnosed each year.

Lung cancer is rare among children and young adults. It is usually found in people older than fifty. The average age at diagnosis is sixty. 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 and start a new infection. When cancer...