Lung Cancer Staging
Is the assessment of the extent to which a lung cancer has spread from its original source. As with most cancers, staging is an important determinant of treatment and prognosis. In general, more advanced stages of cancer are less amenable to treatment and have a worse prognosis.
There are several methods by which this assessment is made. They are broadly classified into non-invasive techniques, which generally involve medical imaging of the lungs such as computer tomography (CT) scans, and invasive techniques such as biopsy. Invasive techniques provide additional information because tissue samples can be seen microscopically to determine the type of lung cancer and its grade.
Pattern of progression.
Lung cancer can start in various portions of the lung. From there it spreads in fairly predictable pattern. Typically, if lung cancer spreads, it first goes to close-by lymph nodes, followed by lymph nodes further away located between the lungs in a space called the mediastinum. In the mediastinum, the lung cancer tends at first to stay on the side where the original tumor started. Once it crosses the mediastinal midline, it denotes more advanced, surgically unresectable disease. Lung cancer can also spread to distant organs, for example, the liver or adrenal glands, which constitutes the most advanced stage of the disease called stage IV.
Staging is the process of determining how much cancer there is in the body and where it is located. Staging of lung cancer is of paramount importance as treatment choices are often highly complex, even for physicians with much experience in the field, and the options largely depend on the stage of the disease. The underlying purpose is to describe the extent or severity of an individual's cancer, and to bring together cancers that have similar prognosis and treatment.
Staging information which is obtained prior to surgery, for example by x-rays and endoscopic ultrasound, is called clinical staging.
Staging by surgery is known as pathological staging.
click image for more