Non-Small Cell Lung Cancer - (Stages 0-4)

After non-small cell lung cancer (NSCLC) has been diagnosed in a patient it is given what is called a "stage." This describes both the size of the tumor, and to what extent the tumor has spread within the body. Once diagnosed, a more accurate prognosis (life expectancy) of a patient can be given. There are five main stages of NSCLC (0, 1, 2, 3, 4). Each of these stages is further divided into more specific sub-stages.

(Stages 0-4)

- 0 The cancer has not spread past the inner lining of the lungs; also known as carcinoma in situ (CIS).
- 1 The cancer is localized within the lungs but has not yet spread to the lymph nodes.
- 1A (the tumor is 3 cm or less in diameter).
- 1B (the tumor is greater than 3 cm in diameter).
- 2 The cancer has either spread outside the lungs to the nearby lymph nodes, or has NOT yet spread to the lymph nodes, but is localized in a certain area of the main bronchus (tubes that allow air to pass between the trachea and the lungs). The tumor may also be located in an area where it has invaded the lining of the lungs, or the wall of the chest.
- 2A (the tumor is 3 cm or less and has spread to the lymph nodes).
- 2B (the tumor is greater that 3 cm and has spread to the lymph nodes. It may also be present in the main bronchus region, has invaded the lining of the lungs, or wall of the chest.
- 3 The cancer has spread to the nearby tissue of the lungs.
- 3A (the tumor is lager in size and has spread to the lymph nodes. At this stage multi-tumors of any size may have spread away from the main tumor area).
- 3B (tumors of any size that have spread to distant lymph nodes and have invaded other organs such as the esophagus, the heart, or tumors with malignant pleural effusion [an abnormal amount of fluid in the space between the tissue that lines the inside of the lungs]).
- 4 The cancer has reached its most dangerous stage by having spread to other organs of the body, including another lobe of the lung.

Doctors may often describe NSCLC with a system called TNM. This system is used to further classify lung cancer within its sub-stages. Each letter stands for a different degree (stage) of the disease.

T - (the size of the tumor).
N - (indicates which lymph nodes have been invaded).
M - (defines whether the cancer has metastasized).

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