Staging is based on the results of the physical exam, biopsies, and imaging tests (CT scan, chest x-ray, PET scan, etc.), which are described in the section, "How Is Non-Small Cell Lung Cancer Diagnosed?"

The TNM Staging System

The system used to describe the growth and spread of non-small cell lung cancer (NSCLC) is the American Joint Committee on Cancer (AJCC) TNM staging system. The TNM system describes 3 key pieces of information:

• T indicates the size of the main (primary) tumor and whether it has grown into nearby areas. 
• N describes how much the cancer has spread to nearby (regional) lymph nodes. Lymph nodes are small bean-shaped collections of immune system cells that are important in fighting infections. 
• M indicates whether the cancer has spread (metastasized) to other organs of the body. (The most common sites are the liver, bones, and brain.)

Numbers or letters appear after T, N, and M to provide more details about each of these factors. The numbers 0 through 4 indicate increasing severity. The letter X means "cannot be assessed because the information is not available."

T Categories for Non-small Cell Lung Cancer

TX: Main (primary) tumor can't be assessed, or cancer cells were seen on sputum cytology but no tumor can be found.

T0: No evidence of a primary tumor.

Tis: Cancer is found only in the layer of cells lining the air passages. It has not invaded into deeper lung tissues. This stage is also known as carcinoma in situ.

T1: The tumor is no larger than 3 centimeters (slightly less than 1¼ inches) across, has not reached the membranes that surround the lungs (visceral pleura), and does not affect the main branches of the bronchi.

T2: The tumor has 1 or more of the following features:

• It is larger than 3 centimeters (cm) across. 
• It involves a main bronchus, but is not closer than 2 cm (about ¾ inch) to the carina (the point where the windpipe splits into the left and right main bronchi). 
• It has grown into the membranes that surround the lungs (visceral pleura). 
• The tumor partially clogs the airways, but this has not caused the entire lung to collapse or develop pneumonia.

T3: The tumor can be any size and has 1 or more of the following features:

• It has grown into the chest wall, the breathing muscle that separates the chest from the abdomen (diaphragm), the membranes surrounding the space between the two lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium). 
• It invades a main bronchus and is closer than 2 cm (about ¾ inch) to the carina, but it does not involve the carina itself. 
• It has grown into the airways enough to cause an entire lung to collapse or to cause pneumonia in the entire lung.

T4: The cancer has 1 or more of the following features:

• A tumor of any size has grown into the space behind the chest bone and in front of the heart (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe, the esophagus (tube connecting the throat to the stomach), the backbone, or the carina. 
• Two or more separate tumor nodules are present in the same lobe of a lung. 
• There is a fluid containing cancer cells in the space surrounding the lung (a malignant pleural effusion).

N Categories for Non-small Cell Lung Cancer

NX: Nearby lymph nodes cannot be assessed.

N0: No spread to nearby lymph nodes.

N1: Spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). Affected lymph nodes are on the same side as the primary tumor(s).

N2: Spread to lymph nodes around the carina (the point where the windpipe splits into the left and right bronchi) or in the space behind the breastbone and in front of the heart (mediastinum). Affected lymph nodes are on the same side as the primary tumor.

N3: Spread to lymph nodes near the collarbone on either side, and/or spread to hilar or mediastinal lymph nodes on the side opposite the primary tumor.

M Categories for Non-small Cell Lung Cancer

M0: No spread to distant organs or areas. This includes other lobes of the lungs, lymph nodes further away than those mentioned in the N stages above, and other organs or tissues such as the liver, bones, or brain.

M1: The cancer has spread to 1 or more distant sites. This can be to another lobe of the lung, to distant lymph nodes, or to other organs.

Stage Grouping for Non-small Cell Lung Cancer

Once the T, N, and M categories have been assigned, this information is combined (stage grouping) to assign an overall stage of 0, I, II, III, or IV. Some stages are subdivided into A and B. The stages identify tumor types that have a similar prognosis and thus are treated in a similar way. Patients with lower stage numbers tend to have a better prognosis.

Occult Cancer

TX, N0, M0: Cancer cells are seen in a sample of sputum or other lung fluids, but the location of the cancer can't be determined.

Stage 0

Tis, N0, M0: The cancer is found only in the layer of cells lining the air passages. It has not invaded deeper into other lung tissues and has not spread to lymph nodes or distant sites.

Stage IA

T1, N0, M0: The cancer is no larger than 3 centimeters (cm) across, has not reached the membranes that surround the lungs, and does not affect the main branches of the bronchi. It has not spread to lymph nodes or distant sites.

Stage IB

T2, N0, M0: The cancer has 1 or more of the following features:

• The main tumor is larger than 3 cm across. 
• The tumor involves a main bronchus, but is not within 2 cm of the carina. 
• The tumor has grown into the visceral pleura (the membranes surrounding the lungs). 
• The cancer is partially clogging the airways.

The cancer has not spread to lymph nodes or distant sites.

Stage IIA

T1, N1, M0: The cancer is no larger than 3 centimeters, has not grown into the membranes that surround the lungs, and does not affect the main branches of the bronchi. It has spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). It has not spread to distant sites.

Stage IIB

There are 2 combinations of categories that make up this stage.

T2, N1, M0: The cancer has 1 or more of the following features:

• The main tumor is larger than 3 cm across. 
• The tumor involves a main bronchus, but is not within 2 cm of the carina. 
• The tumor has grown into the visceral pleura (the membranes surrounding the lungs). 
• The cancer is partially clogging the airways.

It has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). It has not spread to distant sites.

T3, N0, M0: The main tumor can be any size and has 1 or more of the following features:

• It has grown into the chest wall, the breathing muscle that separates the chest from the abdomen (diaphragm), the membranes surrounding the space between the two lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium). 
• It invades a main bronchus and is closer than 2 cm (about ¾ inch) to the carina, but it does not involve the carina itself. 
• It has grown into the airways enough to cause an entire lung to collapse or to cause pneumonia in the entire lung.

The cancer has not spread to lymph nodes or distant sites.

Stage IIIA

There are 4 main combinations of categories that make up this stage.

T1, N2, M0: The cancer is no larger than 3 centimeters, has not grown into the membranes that surround the lungs, and does not affect the main branches of the bronchi. The cancer has spread to lymph nodes around the carina (the point where the windpipe splits into the left and right bronchi) or in the space behind the breastbone and in front of the heart (mediastinum). Affected lymph nodes are on the same side as the primary tumor. The cancer has not spread to distant sites.

T2, N2, M0: The cancer has 1 or more of the following features:

• The main tumor is larger than 3 cm across. 
• The tumor involves a main bronchus, but is not within 2 cm of the carina. 
• The tumor has grown into the visceral pleura (the membranes surrounding the lungs). 
• The cancer is partially clogging the airways.

The cancer has also spread to lymph nodes around the carina (the point where the windpipe splits into the left and right bronchi) or in the space behind the breastbone and in front of the heart (mediastinum). Affected lymph nodes are on the same side as the primary tumor. The cancer has not spread to distant sites.

T3, N1, M0: The tumor can be any size and has 1 or more of the following features:

• It has grown into the chest wall, the breathing muscle that separates the chest from the abdomen (diaphragm), the membranes surrounding the space between the two lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium). 
• It invades a main bronchus and is closer than 2 cm (about ¾ inch) to the carina, but it does not involve the carina itself. 
• It has grown into the airways enough to cause an entire lung to collapse or to cause pneumonia in the entire lung.

It has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). It has not spread to distant sites.

T3, N2, M0: The tumor can be any size and has 1 or more of the following features:

• It has grown into the chest wall, the breathing muscle that separates the chest from the abdomen (diaphragm), the membranes surrounding the space between the two lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium). 
• It invades a main bronchus and is closer than 2 cm (about ¾ inch) to the carina, but it does not involve the carina itself. 
• It has grown into the airways enough to cause an entire lung to collapse or to cause pneumonia in the entire lung.

The cancer has also spread to lymph nodes around the carina (the point where the windpipe splits into the left and right bronchi) or in the space behind the breastbone and in front of the heart (mediastinum). Affected lymph nodes are on the same side as the primary tumor. The cancer has not spread to distant sites.

Stage IIIB

There are 2 combinations of categories that make up this stage.

Any T, N3, M0: The cancer can be of any size. It may or may not have grown into nearby structures or caused pneumonia or lung collapse. It has spread to lymph nodes near the collarbone on either side, and/or has spread to hilar or mediastinal lymph nodes on the side opposite the primary tumor. The cancer has not spread to distant sites.

T4, any N, M0: The cancer has 1 or more of the following features:

• A tumor of any size has grown into the space behind the chest bone and in front of the heart (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe, the esophagus (tube connecting the throat to the stomach), the backbone, or the carina. 
• Two or more separate tumor nodules are present in the same lobe of a lung. 
• There is a fluid containing cancer cells in the space surrounding the lung (a malignant pleural effusion).

The cancer may or may not have spread to nearby lymph nodes. It has not spread to distant sites.

Stage IV

Any T, Any N, M1: The cancer can be any size and may or may not have grown into nearby structures or reached nearby lymph nodes. It has spread to distant sites.

Non-Small Cell Lung Cancer Survival Rates by Stage

The numbers below are relative survival rates calculated from the American College of Surgeons National Cancer Data Base, based on people who were diagnosed with non-small cell lung cancer in 1992 and 1993. There are some important points to note about these numbers:

• The 5-year survival rate refers to the percentage of patients who live at least 5 years after being diagnosed. Many of these patients live much longer than 5 years after diagnosis. Five-year relative survival rates (such as the numbers below) don't include patients who die from other causes. They are considered to be a more accurate way to describe the outlook for patients with a particular type and stage of cancer. 
• These numbers were derived from patients treated several years ago. While they are among the most current numbers we have available, improvements in treatment since then mean that the survival rates for people now being diagnosed with these cancers may be higher. 
• While survival statistics can sometimes be useful as a general guide, they may not accurately represent any one person's prognosis. A number of other factors, including other tumor characteristics and a person's age and general health, can also affect outlook. Your doctor is likely to be a good source as to whether these numbers may apply to you, as he or she is familiar with the aspects of your particular situation.

Stage	5-year Relative Survival Rate
I	47%
II	26%
III	8%
IV	2%

While these survival rates aren't broken down by substages, the rates will likely be higher than those above for the A subgroups and lower for the B subgroups.