Lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung.The lungs are a pair of cone-shaped breathing organs in the chest. The lungs bring oxygen into the body as you breathe in. They release carbon dioxide, a waste product of the body's cells, as you breathe out. Each lung has sections called lobes. The left lung has two lobes. The right lung is slightly larger, and has three lobes. A thin membrane called the pleura surrounds the lungs. Two tubes called bronchi lead from the trachea (windpipe) to the right and left lungs. The bronchi are sometimes also involved in lung cancer. Tiny air sacs called alveoli and small tubes called bronchioles make up the inside of the lungs. Anatomy of the respiratory system, showing the trachea and both lungs and their lobes and airways. Lymph nodes and the diaphragm are also shown. Oxygen is inhaled into the lungs and passes through the thin membranes of the alveoli and into the bloodstream (see inset).There are two
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BackgroundIn NSCLC, the determination of stage is important in terms of therapeutic and prognostic implications. Careful initial diagnostic evaluation to define the location and to determine the extent of primary and metastatic tumor involvement is critical for the appropriate care of patients. In general, symptoms, physical signs, laboratory findings, or perceived risk of distant metastasis lead to an evaluation for distant metastatic disease. Additional tests such as bone scans and computed tomography (CT)/magnetic resonance imaging (MRI) of the brain may be performed if initial assessments suggest metastases or if patients with stage III disease are under consideration for aggressive local and combined modality treatments.Stage has a critical role in the selection of therapy. The stage of disease is based on a combination of clinical factors and pathological factors. The distinction
This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http://cancer.gov or call 1-800-4-CANCER.Lung Cancer Screening