What is staging and why is it important?

The STAGE of lung cancer describes if and where the cancer has spread. The cancer has to be staged before treatment options can be known. Imaging tests, biopsies and other tests all help to tell the stage.

Lung cancer is staged using the TNM staging system. TNM is one of the most commonly used cancer staging systems in the world.

TNM looks at the size of the tumor (T); if and how much the cancer has spread to the lymph nodes (N); & if and how far the cancer has spread beyond the lymph nodes (M for metastasis).

Non-small cell lung cancer: To learn more about treatments for each stage,  click stage I, stage II, stage III and stage IV .

Small cell lung cancer: Small cell is also staged using TNM but the older way of staging it may still be in use:

Limited-Stage, which means the cancer has not spread beyond one lung and the lymph nodes near that lung

Or

Extensive-Stage, which means the cancer is in both lungs or has spread to other areas of the body.

How Does The TNM Staging System Work?

T is for Tumor

How big is the tumor? Where is it located? Has it spread to nearby tissue?

TX Tumors are too small for testing or cannot be found with tests.
T0 No primary tumor has been found.
Tis There are abnormal or cancer cells in airways that have not spread to other lung tissue.
T1 Tumors are only in the lungs and are 3 cm or smaller.
T1mi Tumors grow only along the surface of lung tissue and are not 0.5 cm deep into the tissue of the lung.
T1a Tumors are 1 cm or smaller and are at least 0.5 cm or deeper into the tissue of the lung.
T1b Tumors are larger than 1 cm but smaller than 2 cm and are at least 0.5 cm deep into the tissue of the lung.
T1c Tumors are larger than 2 cm but smaller than 3 cm and are at least 0.5 cm deep into the tissue.
T2 Tumors are larger than 3 cm but smaller than 5 cm

AND have grown into the main bronchus (the two airway tubes that split off of the windpipe) OR have grown into the lung’s inner lining (visceral pleura) OR have caused lung collapse (atelectasis) or swelling (pneumonitis).

T2a Tumors are 4 cm or smaller. Other features may or may not be present but smaller tumors with other features are also rated T2a.
T2b Tumors are larger than 4 cm. Other features may or may not be present.
T3  Tumors are larger than 5 cm but not larger than 7 cm

AND have grown into the lung’s outer lining (parietal pleura) or nearby sites including chest wall, phrenic nerve OR have grown into the lining of the heart (pericardium) OR primary and secondary tumors are in the same lobe.

T4 Tumors are larger than 7 cm

AND have grown into the diaphragm, mediastinum, heart or its major blood vessels, windpipe (trachea), recurrent laryngeal nerve, carina, esophagus, or spine OR there are secondary tumors in the same lung but in a different lobe than the primary tumor.

N is for Lymph Node

Has the cancer spread to the lymph nodes in and around the lungs? For more information on the lymph system and lymph nodes, see Lymph System

NX Lymph nodes near the cancer have not been tested.
N0 There is no cancer in lymph nodes near the cancer.
N1 Cancer has spread to the lymph nodes near the two airway tubes that split off from the windpipe (peribronchial nodes) and/or to nodes in the center of the chest (hilar nodes) and in the lung (intrapulmonary nodes) with the primary tumor.
N2 Cancer has spread to other nodes in the center of the chest (mediastinal nodes, including subcarinal nodes) near the lung with the primary tumor.
N3 Cancer has spread to nodes in the center of the chest (mediastinal or hilar) near the lung without the primary tumor OR to any nodes in the neck or near the collarbone (supraclavicular or scalene nodes).

M is for Metastasis

Has the cancer spread to areas outside the lymph nodes?

M0 Cancer has not spread to distant sites.
M1 Cancer has spread to distant sites.
M1a Cancer has spread from one lung into the other OR into the lining of the lung  (pleura) and has formed secondary nodule(s) OR into the lining of the heart  (pericardium) and has formed secondary nodule(s) OR into the fluid around the lungs or the heart.
M1b Cancer has spread to one site outside the chest area.
M1c Cancer has spread to more than one site outside the chest area.

Stages

After the Tumor (T), Lymph Nodes (N) and Metastasis (M) are known, the cancer then is staged:

Overall Stage T N M
Stage 0 Tis (in situ) N0 M0
Stage IA1 T1mi, a N0 M0
Stage IA2 T1b N0 M0
Stage IA3 T1c N0 M0
Stage IB T2a N0 M0
Stage IIA T2b N0 M0
Stage IIB T1a
T1b
T1c
T2a
T2b
T3
N1
N1
N1
N1
N1
No
M0
M0
Mo
M0
M0
Mo
Stage IIIA T1a
T1b
T1c
T2a
T2b
T3
T4
T4
N2
N2
N2
N2
N2
N1
No
N1
M0
M0
M0
M0
M0
Mo
M0
M0
Stage IIIB T1a
T1b
T1c
T2a
T2b
T3
T4
N3
N3
N3
N3
N3
N2
N2
M0
M0
M0
M0
Mo
M0
M0
Stage IIIC T3
T4
N3
N3
M0
M0
Stage IVA Any T
Any T
Any N
Any N
M1a
M1a
Stage IVB Any T Any N M1c

Small Cell Lung Cancer

Small cell lung cancer is most often staged as either limited-stage or extensive-stage.

Limited-Stage

Indicates that the cancer has not spread beyond one lung and the lymph nodes near that lung.

Extensive-Stage

The cancer is in both lungs or has spread to other areas of the body.

Source:

International Association for the Study of Lung Cancer. Goldstraw P, ed. Staging Handbook in Thoracic Oncology. Orange Park: Editorial Rx Press; 2009.

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