Lung Cancer Health Article

Definition

Lung cancer is a disease in which the cells of the lung tissues grow uncontrollably and form tumors. It is the leading cause of death from cancer among both men and women in the United States. The American Cancer Society estimates that in 2001 at least 169,500 new cases of lung cancer will be diagnosed, and that lung cancer will account for 28% of all cancer deaths—approximately 157,400 people.

Types of lung cancer

There are two kinds of lung cancers, primary and secondary. Primary lung cancer starts in the lung itself. Primary lung cancer is divided into small cell lung cancer and non-small cell lung cancer, depending on how the cells look under the microscope. Secondary lung cancer is cancer that starts somewhere else in the body (for example, the breast or urinary bladder) and metastasizes (spreads) to the lungs. Identifying the type of lung cancer is important because treatment varies by type. For example, small cell cancers generally are treated with surgery. On the other hand, surgery is not generally considered beneficial for non-small cell cancers; they are treated with chemotherapy.

Small cell cancer was formerly called oat cell cancer, because the cells resemble oats in their shape. About a fourth of all lung cancers are small cell cancers. This is a very aggressive cancer and spreads to other organs within a short time. It is generally diagnosed in people who are heavy smokers. Non-small cell cancers account for the remaining 75% of primary lung cancers. They can be further subdivided into three categories.

Nearly 30% of non-small cell cancers are squamous cell carcinomas. Squamous cell carcinoma is most often found near the bronchi of patients with a history of smoking. Forty percent of non-small cell cancers are adenocarcinomas, most often found in the outer region of the lung. The remaining 10% are large-cell undifferentiated carcinomas. These rapidly spreading carcinomas may be found throughout the lung.