Lung Cancer (Non-Small Cell)

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Early Detection, Diagnosis, and Staging TOPICS

How is non-small cell lung cancer staged?

The stage of a cancer describes how far it has spread. Your treatment and prognosis (outlook) depend, to a large extent, on the cancer’s stage.

There are actually 2 types of staging descriptions for non-small cell lung cancer (NSCLC).

  • The clinical stage 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?
  • If you have surgery, your doctor can also determine the pathologic stage, which is based on the same factors as the clinical stage, plus what is found as a result of the surgery.

The clinical and pathologic stages may be different in some cases. For example, during surgery the doctor may find cancer in an area that did not show up on imaging tests, which might give the cancer a more advanced pathologic stage.

Because many patients with NSCLC do not have surgery, the clinical stage is often used when describing the extent of this cancer. But when it is available, the pathologic stage is likely to be more accurate than the clinical stage, as it uses the additional information obtained at surgery.

The TNM staging system

The system used to describe the growth and spread of NSCLC is the American Joint Committee on Cancer (AJCC) TNM staging system. The TNM system is based on 3 key pieces of information:

  • T indicates the size of the main (primary) tumor and whether it has grown into nearby areas.
  • N describes the spread of cancer to nearby (regional) lymph nodes. Lymph nodes are small bean-shaped collections of immune system cells to which cancers often spread before going to other parts of the body.
  • M indicates whether the cancer has spread (metastasized) to other organs of the body. (The most common sites are the brain, bones, adrenal glands, liver, kidneys, and the other lung.)

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 TNM staging system is complex and can be hard for patients (and even some doctors) to understand. If you have any questions about the stage of your cancer, ask your doctor to explain it to you.

T categories for lung cancer

TX: The main (primary) tumor can’t be assessed, or cancer cells were seen on sputum cytology or bronchial washing but no tumor can be found.

T0: There is no evidence of a primary tumor.

Tis: The cancer is found only in the top layers of cells lining the air passages. It has not invaded into deeper lung tissues. This is also known as carcinoma in situ.

T1: The tumor is no larger than 3 centimeters (cm)—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.

If the tumor is 2 cm (about 4/5 of an inch) or less across, it is called T1a. If the tumor is larger than 2 cm but not larger than 3 cm across, it is called T1b.

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

  • It is larger than 3 cm across but not larger than 7 cm.
  • 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.

If the tumor is 5 cm or less across, it is called T2a. If the tumor is larger than 5 cm across (but not larger than 7 cm), it is called T2b.

T3: The tumor has 1 or more of the following features:

  • It is larger than 7 cm across.
  • 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.
  • Two or more separate tumor nodules are present in the same lobe of a lung.

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

  • A tumor of any size has grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina.
  • Two or more separate tumor nodules are present in different lobes of the same lung.

N categories for lung cancer

NX: Nearby lymph nodes cannot be assessed.

N0: There is no spread to nearby lymph nodes.

N1: The cancer has 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.

N2: 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 between the lungs (mediastinum). Affected lymph nodes are on the same side as the primary tumor.

N3: The cancer has 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 lung cancer

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

M1a: Any of the following:

  • The cancer has spread to the other lung.
  • Cancer cells are found in the fluid around the lung (called a malignant pleural effusion).
  • Cancer cells are found in the fluid around the heart (called a malignant pericardial effusion).

M1b: The cancer has spread to distant lymph nodes or to other organs such as the liver, bones, or brain.

Stage grouping for lung cancer

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

Occult (hidden) cancer

TX, N0, M0: Cancer cells are seen in a sample of sputum or other lung fluids, but the cancer isn’t found with other tests, so its location can’t be determined.

Stage 0

Tis, N0, M0: The cancer is found only in the top layers 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

T1a/T1b, N0, M0: The cancer is no larger than 3 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

T2a, N0, M0: The cancer has 1 or more of the following features:

  • The main tumor is larger than 3 cm across but not larger than 5 cm.
  • The tumor has grown into a main bronchus, but is not within 2 cm of the carina (and it is not larger than 5 cm).
  • The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is not larger than 5 cm.
  • The tumor is partially clogging the airways (and is not larger than 5 cm).

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

Stage IIA

Three main combinations of categories make up this stage.

T1a/T1b, N1, M0: The cancer is no larger than 3 cm across, 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). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

T2a, N1, M0: The cancer has 1 or more of the following features:

  • The main tumor is larger than 3 cm across but not larger than 5 cm.
  • The tumor has grown into a main bronchus, but is not within 2 cm of the carina (and it is not larger than 5 cm).
  • The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is not larger than 5 cm.
  • The tumor is partially clogging the airways (and is not larger than 5 cm).

The cancer has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

T2b, N0, M0: The cancer has 1 or more of the following features:

  • The main tumor is larger than 5 cm across but not larger than 7 cm.
  • The tumor has grown into a main bronchus, but is not within 2 cm of the carina (and it is between 5 and 7 cm across).
  • The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is between 5 and 7 cm across.
  • The tumor is partially clogging the airways (and is between 5 and 7 cm across).

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

Stage IIB

Two combinations of categories make up this stage.

T2b, N1, M0: The cancer has 1 or more of the following features:

  • The main tumor is larger than 5 cm across but not larger than 7 cm.
  • The tumor has grown into a main bronchus, but is not within 2 cm of the carina (and it is between 5 and 7 cm across).
  • The tumor has grown into the visceral pleura (the membranes surrounding the lungs) and is between 5 and 7 cm across.
  • The cancer is partially clogging the airways (and is between 5 and 7 cm across).

It has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

T3, N0, M0: The main tumor has 1 or more of the following features:

  • It is larger than 7 cm across.
  • 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 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.
  • Two or more separate tumor nodules are present in the same lobe of a lung.

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

Stage IIIA

Three main combinations of categories make up this stage.

T1 to T3, N2, M0: The main tumor can be any size. It has not grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina. It has not spread to different lobes of the same lung.

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 between the lungs (mediastinum). These lymph nodes are on the same side as the main lung tumor. The cancer has not spread to distant sites.

OR

T3, N1, M0: The cancer has 1 or more of the following features:

  • It is larger than 7 cm across.
  • 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 lungs (mediastinal pleura), or membranes of the sac surrounding the heart (parietal pericardium).
  • It invades a main bronchus and is closer than 2 cm to the carina, but it does not involve the carina itself.
  • Two or more separate tumor nodules are present in the same lobe of a lung.
  • 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). These lymph nodes are on the same side as the cancer. It has not spread to distant sites.

OR

T4, N0 or N1, M0: The cancer has 1 or more of the following features:

  • A tumor of any size has grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina.
  • Two or more separate tumor nodules are present in different lobes of the same lung.

It may or may not have spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (hilar lymph nodes). Any affected lymph nodes are on the same side as the cancer. It has not spread to distant sites.

Stage IIIB

Two combinations of categories 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.

OR

T4, N2, M0: The cancer has 1 or more of the following features:

  • A tumor of any size has grown into the space between the lungs (mediastinum), the heart, the large blood vessels near the heart (such as the aorta), the windpipe (trachea), the tube connecting the throat to the stomach (esophagus), the backbone, or the carina.
  • Two or more separate tumor nodules are present in different lobes of the same 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 between the lungs (mediastinum). Affected lymph nodes are on the same side as the main lung tumor. It has not spread to distant sites.

Stage IV

Two combinations of categories make up this stage.

Any T, any N, M1a: The cancer can be any size and may or may not have grown into nearby structures or reached nearby lymph nodes. In addition, any of the following is true:

  • The cancer has spread to the other lung.
  • Cancer cells are found in the fluid around the lung (called a malignant pleural effusion).
  • Cancer cells are found in the fluid around the heart (called a malignant pericardial effusion).

OR

Any T, any N, M1b: 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 lymph nodes or to other organs such as the liver, bones, or brain.


Last Medical Review: 08/15/2014
Last Revised: 08/22/2014