Lung cancer is the most common cancer worldwide, with an estimated 1,600,000 new cases and 1,380,000 deaths in 2008. In the United States, there will be an estimated 221,000 new cases of lung cancer and 157,000 deaths in 2010.
The term lung cancer, or bronchogenic carcinoma, refers to malignancies that originate in the airways or pulmonary parenchyma. Approximately 95 percent of all lung cancers are classified as either small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC). This distinction is essential for staging, treatment, and prognosis. Other cell types comprise about 5 percent of malignancies arising in the lung.
A number of environmental and life-style factors have been associated with the subsequent development of lung cancer, of which cigarette smoking is the most important. Other Environmental factors have been associated with an increased risk for developing lung cancer. These include exposure to second-hand smoke, asbestos, radon, ionizing radiation, and polycyclic aromatic hydrocarbons.
The World Health Organization classification for primary lung cancer recognizes four major histologic cell types: