Staging is a very important part of the lung cancer diagnosis process. The stage finds out if and to what extent the lung cancer has spread from its original location. Knowing the stage will help your oncologist best shape your treatment plan.
The staging system most often used for lung cancer is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 3 key pieces of information:
The size and extent of the main tumor (T)
The spread to nearby (regional) lymph nodes (N)
The spread (metastasis) (M) to other organs of the body
The information gathered from the staging process gives the oncologist a better idea regarding the seriousness of the cancer, what treatments will be the most effective, if there are clinical trials for viable treatment options, and your chances of survival (prognosis).
After determining a diagnosis of small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC), additional testing determines if the cancer cells have spread (metastasized) within the chest or to other parts of the body. This information determines the stage of the disease and treatment plan.
Additional tests and procedures that may be used in the non-small cell lung cancer staging process include:
Lymph node biopsy
Mediastinoscopy: A surgical procedure in which a mediastinoscope is used to examine the organs in the area between the lungs and nearby lymph nodes for cancer. A mediastinoscope is a thin, tube-like instrument with a light and a lens for viewing. It is inserted into the chest through an incision (cut) made at the top of the breastbone.
Anterior mediastinotomy: A surgical procedure to look at the organs and tissues between the lungs and between the breastbone and heart for abnormal areas. This is also called the Chamberlain procedure.
Because staging for NSCLC can be complex, it is important to ask your oncologist to explain it in a way that’s easy to understand. The stages of NSCLC are as follows:
In the occult (hidden) stage, cancer cells are found in sputum (mucus coughed up from the lungs), but no tumor can be found in the lung by imaging or bronchoscopy, or the primary tumor is too small to be checked.
In stage 0, abnormal cells are found in the innermost lining of the lung. These abnormal cells may become cancerous and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ (localized).
Cancer has formed. Stage I is divided into stages IA and IB:
Stage IA
The tumor is in the lung only and is 3 centimeters or smaller.
Stage IB
One or more of the following is true:
The tumor is larger than 3 centimeters.
Cancer has spread to the main bronchus of the lung, and is at least 2 centimeters from the carina (where the trachea joins the bronchi).
Cancer has spread to the innermost layer of the membrane that covers the lungs.
The tumor partly blocks the bronchi or bronchioles and part of the lung has collapsed or developed pneumonitis (inflammation of the lung).
Stage II is divided into stages IIA and IIB:
Stage IIA
The tumor is 3 centimeters or smaller and cancer has spread to nearby lymph nodes on the same side of the chest as the tumor.
Stage IIB
Cancer has spread to nearby lymph nodes on the same side of the chest as the tumor and one or more of the following is true:
The tumor is larger than 3 centimeters.
Cancer has spread to the main bronchus of the lung and is 2 centimeters or more from the carina (where the trachea joins the bronchi).
Cancer has spread to the innermost layer of the membrane that covers the lungs.
The tumor partly blocks the bronchi or bronchioles and part of the lung has collapsed or developed pneumonitis (inflammation of the lung).
OR
Cancer has not spread to lymph nodes and one or more of the following is true:
The tumor may be any size, and cancer has spread to the chest wall, or the diaphragm, or the pleura between the lungs, or membranes surrounding the heart.
Cancer has spread to the main bronchus of the lung and is no more than 2 centimeters from the carina (where the trachea meets the bronchi), but has not spread to the trachea.
Cancer blocks the bronchi or bronchioles, and the whole lung has collapsed or developed pneumonitis (inflammation of the lung).
Stage III is divided into stages IIIA and IIIB:
Stage IIIA
Cancer has spread to lymph nodes on the same side of the chest as the tumor. The tumor may be any size. One or more of the following is true:
Cancer may have spread to the main bronchus, the chest wall, the diaphragm, the pleura around the lungs, or the membrane around the heart, but has not spread to the trachea.
Part or all of the lung may have collapsed or developed pneumonitis (inflammation of the lung).
Stage IIIB
The tumor may be any size and has spread:
To lymph nodes above the collarbone or in the opposite side of the chest from the tumor; and/or to any of the following:
Heart
Major blood vessels that lead to or from the heart
Chest wall
Diaphragm
Trachea
Esophagus
Sternum (chest bone) or backbone
More than one place in the same lobe of the lung
The fluid of the pleural cavity surrounding the lung
In Stage IV, cancer may have spread to lymph nodes and has spread to another lobe of the lungs or to other parts of the body, such as the brain, liver, adrenal glands, kidneys, or bone.
