Lung cancer is the most frequently lethal cancer in the United States. Among all causes of death, lung cancer ranks second after heart disease for males, and third after heart and cerebrovascular disease for females. In 2002 alone, over 150,000 people in the United States died of lung cancer.

Cancers form when certain cells in the body grow and multiply in an uncontrolled fashion. When such uncontrolled growth affects lung tissues, a lung cancer forms. Lung cancer is classified into two main types- small cell lung cancer and non-small cell lung cancer. An estimated 80 percent of lung cancer patients have non-small cell lung cancer.

Smoking or inhaling second hand smoke, environmental exposures such as asbestos and radon gas, and a family history of lung cancer increase the risk of an individual getting lung cancer. However, some lung cancers arise in the absence of these risk factors. Factors that may protect people from lung cancer are not smoking, avoiding second hand smoke, a diet rich in fresh vegetables and fruit, and limiting exposure to potential carcinogens in the environment such as radon.

About 25 percent of people with lung cancer report no symptoms at the time of diagnosis. In the remainder, symptoms and signs vary, and may include breathlessness, a long lasting cough, coughing up blood, chest pain, wheezing, repeated chest infections, fever, and weight loss. A diagnosis of lung cancer is made on the basis of cell type, x-ray findings and symptoms. The cancer is then staged depending on the extent of its spread within the chest cavity and to other parts of the body. Treatment of lung cancer depends on the cell type and on the stage of cancer at the time of diagnosis. Treatment typically includes surgery, chemotherapy and radiation. Survival rates depend on the type and stage of lung cancer at the time of diagnosis.