Lung cancer is among the most lethal cancers worldwide. In 2010, the cancer will be diagnosed in 222,000 Americans, and more than 157,000 patients will die from lung cancer each year.
Although smoking accounts for the majority of lung cancers, exposure to pollutants in the atmosphere, asbestos, irradiation and perhaps radon can lead to lung cancer in nonsmokers. While the overall incidence and deaths from lung cancer are declining, deaths are highest among black males followed closely by white males. Overall, lung cancer costs the health care system more than $10 billion annually. By the time the diagnosis of lung cancer is made, most cancers have spread widely and the cure rate is very small. In general, the majority of lung cancers are identified incidentally by X-ray. Common symptoms include a change in the character of a cough -- a cough that persists for long periods of time and coughing up blood (hemoptysis). About 25 percent of patients experience chest pain that is usually dull and persistent. Lung cancer should always be suspected in a patient who has had multiple infections in the same part of the lung. Frequently, the first sign of the disease is caused by the spread of the lung cancer to other parts of the body. Cancer in bone may lead to pain or fractures, and if it spreads to the brain, it may cause weakness, stroke, visual changes or seizures. Additionally, the release of molecules from the cancer may lead to unusual symptoms, including swelling of the nail beds, anemia, elevated calcium concentrations in the blood, muscle weakness, skin rashes and degeneration of the brain. Weight loss, severe fatigue and electrolyte abnormalities in the blood are also common findings. Currently, only 13 percent of patients diagnosed with lung cancer survive longer than five years, which is primarily related to the time of diagnosis and progression of disease. But more than 50 percent of patients will live for five years -- if the cancer is diagnosed while the disease is localized to a small part of the lung and amenable to cure by surgery or radiotherapy. By contrast, if the disease has started to spread throughout the body at diagnosis, survival is only 2 percent. In the hope of improving the cure rate, screening tests aimed at early detection of the disease have always been a major research priority. Unfortunately, routine X-rays of the lung in individuals at high risk of developing lung cancer have proved to be of no value; they do not lead to earlier detection of the disease or improvement in mortality rates.