Lung cancer is an uncontrolled, extremely deadly division of cells in the lung. In most developed countries, it kills more men and women than any other form of cancer. The death rate is high because many lung cancers have spread through the body by the time symptoms appear. Once lung cancer has spread, it is extremely difficult to cure.
Smoking causes most cases of lung cancer. The risk of developing lung cancer increases according to the length of time and the amount a person smokes. Exposure to secondhand smoke also increases risk. Other causes include long-term exposure to a radioactive gas called radon or to airborne asbestos fibers (see Asbestos ; Radon ; Smoking ).
Symptoms of lung cancer include persistent cough, weight loss, shortness of breath, coughing up blood, chest pain, or a hoarse voice. If lung cancer is suspected, doctors may begin their examination by examining a patient’s sputum (coughed-up material) for cancer cells. Patients may also have a chest X ray to reveal suspicious masses or other signs of lung disease.
Doctors further investigate abnormal lung areas by obtaining a biopsy (sample of tissue) and examining it under a microscope. In one biopsy procedure, doctors pass a thin, lighted tube called a bronchoscope << BRONG kuh skohp >> into the bronchi << BRONG ky >> . The bronchi are the lung’s breathing tubes, where most cancers form. Doctors can test other lung parts with a technique called video thoracoscopy << `thawr` uh KOS kuh pee >> . In this technique, tiny cameras inserted into the chest send detailed pictures to a big screen, enabling doctors to find and sample abnormalities.
If diagnostic tests show cancer, doctors identify the type of lung cell from which the cancer developed. The various types of cells respond differently to treatments. Treatment also depends on whether the cancer has spread beyond the lung. Many lung cancers spread first to lymph nodes in the chest. These nodes are small masses of tissue that help fight disease by filtering out bacteria and other harmful particles. Other sites invaded by lung cancer include bones, the brain, and the liver.
Doctors can sometimes cure patients whose cancer has not spread. If cancer appears confined to the lung and the patient is otherwise healthy, surgeons usually remove all or part of the lung. During surgery, doctors also remove lymph nodes and test them for cancer cells.
Few patients whose cancer has spread can be cured. Treatment of these patients aims at extending life and reducing pain. Doctors may prescribe drug treatments—called chemotherapy—or radiation therapy to try to shrink tumors and relieve symptoms.
See also Bronchoscope ; Cancer ; Lung.
