What is Lung Cancer?

Lung cancer is the abnormal growth of cells in the lung resulting in a lung tumor. If the abnormal cells originated as lung cancer cells, the resulting collection of cells is called a primary lung tumor. If the abnormal cells originated in another part of the body, such as the colon or liver, and were carried to the lungs by the blood or other bodily fluids, then it is considered a metastatic lung tumor.1 


More than 215,000 cases of primary lung cancer cases are expected to be diagnosed in the United States in 2008. Lung cancer is the leading cause of cancer death in both men and women, and is expected to result in approximately 161,840 deaths – or about 29% of all cancer deaths – in the U.S. this year.2 About 13% of primary lung tumors are considered small cell, including oat cell cancer, mixed small cell/large cell carcinoma and combined small cell carcinoma. The remaining 87% of lung tumors are classified as non-small cell,2 which include squamous cell carcinoma, large cell carcinoma and adenocarcinoma.