What is Lung Cancer?
Lung cancers are classified according to the type of cell present in the tumor. The majority are referred to as non�small cell carcinomas. These include squamous cell or epidermoid carcinomas (the most common type worldwide), adenocarcinomas, and large cell carcinomas. Small cell carcinoma (which includes the subtypes oat cell and intermediate) comprises approximately 20% to 25% of lung cancers; it often has metastasized by the time it is detected. Lung cancer most commonly spreads to the brain, bone, liver, or bone marrow. Lung cancer, cancerthat originates in the tissues of the lungs. Lung cancer is the leading cause of cancer death in the United States in both men and women. Like other cancers, lung cancer occurs after repeated insults to the genetic material of the cell. By far the most common source of these insults is tobacco smoke, which is responsible for about 85% of U.S. lung cancer deaths (see smoking). The incidence of lung cancer in other countries follows their smoking patterns. Some other carcinogens known to cause lung cancer are found in the workplace. These include bischloromethyl ether and chloromethyl ether in chemical workers, arsenic in copper smelting, and asbestos in shipbuilders and other asbestos workers. Radon poses a risk to uranium and fluorspar miners and may pose a risk in some private residences as well. African Americans have a higher incidence of lung cancer than European Americans, even after adjusting for smoking.
