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After someone is diagnosed with non-small cell lung cancer (NSCLC), doctors will try to figure out if it has spread, and if so, how far. This is called staging or finding the cancer's stage.
This process is called staging. The stage of a cancer describes how much and where the cancer is in the body. It helps determine how best to treat it. Doctors also use a cancer’s stage when talking about survival statistics.
The earliest stage of NSCLC is stage 0 (also called carcinoma in situ, or CIS). Other stages range from I (1) through IV (4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV, means cancer has spread more. And within a stage, an earlier letter (or number) means a lower stage. Although each person’s cancer experience is unique, cancers with similar stages tend to have a similar outlook and are often treated in much the same way.
The staging system most often used for NSCLC is the American Joint Committee on Cancer (AJCC) TNM system, which is based on 3 key pieces of information:
Numbers or letters after T, N, and M provide more details about each of these factors. Higher numbers mean the cancer is more advanced. Once a person’s T, N, and M categories have been determined, this information is combined in a process called stage grouping to assign an overall stage. For more information, see Cancer Staging.
The system described below is the most recent version of the AJCC system, effective as of January 2018.
NSCLC is typically given a clinical stage based on the results of a physical exam, biopsy, and imaging tests (as described in Tests for Lung Cancer). If surgery is done, the pathologic stage (also called the surgical stage) is determined by examining tissue removed during the operation.
Staging for NSCLC can be complex, so ask your doctor to explain it to you in a way you understand.
AJCC Stage |
Stage grouping |
Stage description* |
Occult (hidden) cancer |
TX N0 M0 |
The main tumor can’t be assessed for some reason, or 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 (TX). The cancer is not thought to have spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
0 |
Tis N0 M0 |
The tumor is found only in the top layers of cells lining the air passages, but it has not invaded deeper into other lung tissues (Tis). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
IA1 |
T1mi N0 M0 |
The cancer is a minimally invasive adenocarcinoma. The tumor is no larger than 3 centimeters (cm) across, and the part that has invaded into deeper lung tissues is no more than ½ cm across. The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
OR |
||
T1a N0 M0 |
The tumor is no larger than 1 cm across, it has not reached the membranes that surround the lungs, and it does not affect the main branches of the bronchi (T1a). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
|
IA2 |
T1b N0 M0 |
The tumor is larger than 1 cm but no larger than 2 cm across. It has not reached the membranes that surround the lungs, and it does not affect the main branches of the bronchi (T1b). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
IA3 |
T1c N0 M0 |
The tumor is larger than 2 cm but no larger than 3 cm across. It has not reached the membranes that surround the lungs, and it does not affect the main branches of the bronchi (T1c). The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
IB |
T2a N0 M0 |
The tumor has one or more of the following features (T2a):
The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
IIA |
T2b N0 M0 |
The tumor has one or more of the following features (T2b):
The cancer has not spread to nearby lymph nodes (N0) or to distant parts of the body (M0). |
IIB |
T1a/T1b/T1c N1 M0 |
The tumor 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 (T1). It has spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (peribronchial, hilar, or intrapulmonary lymph nodes). These lymph nodes are on the same side as the cancer (N1). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T2a/T2b N1 M0 |
The tumor has one or more of the following features (T2):
The cancer has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (peribronchial, hilar, or intrapulmonary lymph nodes). These lymph nodes are on the same side as the cancer (N1). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T3 N0 M0 |
The tumor has one or more of the following features (T3):
The cancer has not spread to nearby lymph nodes (N0) or distant parts of the body (M0). |
|
IIIA |
T1a/T1b/T1c N2 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 (T1). The cancer has spread to lymph nodes below 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 (N2). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T2a/T2b N2 M0 |
The tumor has one or more of the following features (T2):
The cancer has spread to lymph nodes below 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 (N2). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T3 N1 M0 |
The tumor has one or more of the following features (T3):
The cancer has also spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (peribronchial, hilar, and intrapulmonary lymph nodes). These lymph nodes are on the same side as the cancer (N1). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4 N0 or N1 M0 |
The tumor has one or more of the following features (T4):
The cancer may or may not have spread to lymph nodes within the lung and/or around the area where the bronchus enters the lung (peribronchial, hilar, or intrapulmonary lymph nodes). Any affected lymph nodes are on the same side as the cancer (N0 or N1). The cancer has not spread to distant parts of the body (M0). |
|
IIIB
|
T1a/T1b/T1c N3 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 (T1). The cancer has spread to lymph nodes above the collarbone on either side of the body, and/or has spread to hilar or mediastinal lymph nodes on the other side of the body from the main tumor (N3). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T2a/T2b N3 M0 |
The tumor has one or more of the following features (T2):
The cancer has spread to lymph nodes above the collarbone on either side of the body, and/or has spread to hilar or mediastinal lymph nodes on the other side of the body from the main tumor (N3). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T3 N2 M0 |
The tumor has one or more of the following features (T3):
The cancer has spread to lymph nodes below 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 (N2). The cancer has not spread to distant parts of the body (M0). |
|
OR |
||
T4 N2 M0 |
The tumor has one or more of the following features (T4):
The cancer has spread to lymph nodes below 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 (N2). The cancer has not spread to distant parts of the body (M0). |
|
IIIC |
T3 N3 M0 |
The tumor has one or more of the following features (T3):
The cancer has spread to lymph nodes above the collarbone on either side of the body, and/or has spread to hilar or mediastinal lymph nodes on the other side of the body from the main tumor (N3). The cancer has not spread to distant parts of the body (M0). |
OR |
||
T4 N3 M0 |
The tumor has one or more of the following features (T4):
The cancer has spread to lymph nodes above the collarbone on either side of the body, and/or has spread to hilar or mediastinal lymph nodes on the other side of the body from the main tumor (N3). The cancer has not spread to distant parts of the body (M0). |
|
IVA |
Any T Any N M1a |
The cancer can be any size and may or may not have grown into nearby structures (any T). It may or may not have reached nearby lymph nodes (any N). In addition, any of the following is true (M1a):
|
OR |
||
Any T Any N M1b |
The cancer can be any size and may or may not have grown into nearby structures (any T). It may or may not have reached nearby lymph nodes (any N). It has spread as a single tumor outside of the chest, such as to a distant lymph node or an organ such as the liver, bones, or brain (M1b). |
|
IVB |
Any T Any N M1c |
The cancer can be any size and may or may not have grown into nearby structures (any T). It may or may not have reached nearby lymph nodes (any N). It has spread as more than one tumor outside the chest, such as to distant lymph nodes and/or to other organs such as the liver, bones, or brain (M1c). |
*The following additional categories are not listed in the table above:
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
American Joint Committee on Cancer. Lung. In: AJCC Cancer Staging Manual. 8th ed. New York, NY: Springer; 2017: 431-456.
Last Revised: January 29, 2024
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
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