Lung cancer is the malignant transformation and expansion of lung tissue, and is the most lethal of all cancers worldwide, responsible for 1.2 million deaths annually. It is caused predominantly by cigarette smoking, and predominantly affects men, with it being the leading cause of death of men between the ages of 40 and 65. With increased smoking among women, it is now occuring in women but it is less common.[1] While some people who have never smoked do still get lung cancer, this appears to be due to a combination of genetic factors[2] and exposure to secondhand smoke. Air pollution may also contribute to the development of lung cancer.[5][6][7]
Current research indicates that the factor with the greatest impact on risk of lung cancer is long-term exposure to inhaled carcinogens. The most common means of such exposure is tobacco smoke.
Treatment and prognosis depend upon the histological type of cancer, the stage (degree of spread), and the patient's performance status. Treatments include surgery, chemotherapy, and radiotherapy.
