Lung Cancer


The stage of your cancer describes how far it has spread. Your doctors will determine the extent of your cancer, its location and whether it has spread to nearby organs or to other parts of the body.

Lung cancer may be staged twice. First, your doctor will evaluate the results of your physical exams, biopsies and imaging tests to assign a stage. This stage is called the clinical stage. If you have surgery, your cancer may also be assigned a pathologic stage based on the results from surgery. Staging helps your doctor select the most effective treatment plan for you.

Your doctor and the pathologist will classify the stage of the lung cancer according to the tumor, node, metastasis (TNM) system developed by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC). This system is based on data from around the world collected by the International Association for the Study of Lung Cancer (IASLC) (see Table 2). The system considers the size and location of the tumor (T), whether cancer cells are found in nearby lymph nodes (N) and whether the cancer has metastasized (M), or spread, to other parts of the body. The TNM classifications are then used to determine the overall stage (see Table 1). Lung cancer is staged from Stage 0 (in situ disease, or cancer that has not grown into nearby tissues or spread outside the lung) to Stage IV (cancer that has spread to more than one area in the other lung, the fluid surrounding the lung or heart or distant body parts) (see Staging Illustrations). If lung cancer metastasizes, it is most likely to spread to the adrenal glands, bone, brain, liver or the other lung.

The TNM system is the preferred source for staging the types of non-small cell lung cancer. Limited-stage small cell lung cancer is on only one side of the chest, whereas extensive-stage small cell lung cancer has spread throughout the lung, to the other lung, to lymph nodes on the other side of the chest, or to other parts of the body.

Table 1. Stages of lung cancer

Stage TNM classifications
Occult carcinoma TX, N0, M0
0 Tis, N0, M0
IA1 T1mi, N0, M0
T1a, N0, M0
IA2 T1b, N0, M0
IA3 T1c, N0, M0
IB T2a, N0, M0
T2b, N0, M0
T1a or T1b or T1c, N1, M0
T2a or T2b, N1, M0
T3, N0, M0
T1a or T1b or T1c, N2, M0
T2a or T2b, N2, M0
T3, N1, M0
T4, N0 or N1, M0
T1a or T1b or T1c, N3, M0
T2a or T2b, N3, M0
T3, N2, M0
T4, N2, M0
T3, N3, M0
T4, N3, M0
Any T, Any N, M1
Any T, Any N, M1a or M1b
Any T, Any N, M1c


Table 2. AJCC system for classifying lung cancer

Category Definition
Tumor (T)
TX Primary tumor cannot be assessed, or tumor proven by the presence of malignant (cancerous) cells in sputum (mucus that has been coughed up) or bronchial washings (cells collected from inside the airways) but not visualized by imaging or bronchoscopy.
T0 No evidence of primary tumor.
Tis Carcinoma in situ.
Squamous cell carcinoma in situ (SCIS).
Adenocarcinoma in situ (AIS): adenocarcinoma with pure lepidic pattern (on the alveolar lining), ≤ (not more than) 3cm in greatest dimension.
Tumor ≤ (not more than) 3 cm in greatest dimension, surrounded by lung or visceral pleura (membrane surrounding the lung), without bronchoscopic evidence of invasion more proximal than the lobar bronchus (i.e., not in the main bronchus).
Minimally invasive adenocarcinoma: adenocarcinoma (≤ [not more than] 3 cm in greatest dimension) with a predominantly lepidic pattern (on the alveolar lining) and ≤ (not more than) 5 mm invasion in greatest dimension.
Tumor ≤ (not more than) 1 cm in greatest dimension.
Tumor > (more than) 1 cm but ≤ (not more than) 2 cm in greatest dimension.
Tumor > (more than) 2 cm but ≤ (not more than) 3 cm in greatest dimension.
Tumor > (more than) 3 cm but ≤ (not more than) 5 cm or having any of the following features:
    • Involves the main bronchus regardless of distance to the carina (ridge at the base
      of the trachea), but without involvement of the carina.
    • Invades visceral pleura (membrane surrounding the lung).
    • Associated with atelectasis (collapse of part of the lung) or obstructive pneumonitis
      (inflammation of lung tissues) that extends to the hilar region, involving part or all
      of the lung.
Tumor > (more than) 3 cm but ≤ (not more than) 4 cm in greatest dimension.
Tumor > (more than) 4 cm but ≤ (not more than) 5 cm in greatest dimension.
T3 Tumor > (more than) 5 cm but ≤ (not more than) 7 cm in greatest dimension or directly invading any of the following: parietal pleura (outer lung membrane), chest wall (including superior sulcus tumors), phrenic nerve (nerve that helps control breathing), parietal pericardium; or separate tumor nodule(s) in the same lobe as the primary.
T4 Tumor > (more than) 7 cm or tumor of any size invading one or more of the following: diaphragm, mediastinum (area between the lungs), heart, great vessels, trachea (windpipe), recurrent laryngeal nerve (nerve that helps speech), esophagus, vertebral body, or carina (at base of the trachea); separate tumor nodule(s) in an ipsilateral lobe (lobe that is on the same side of the body) different from that of the primary.
Node (N)
NX Regional lymph nodes cannot be assessed.
N0 No regional lymph node metastasis.
N1 Metastasis in ipsilateral (on the same side) peribronchial and/or ipsilateral hilar lymph nodes and intrapulmonary nodes, including involvement by direct extension.
N2 Metastasis in ipsilateral (on the same side) mediastinal and/or subcarinal lymph node(s).
N3 Metastasis in contralateral (on the opposite side) mediastinal, contralateral hilar, ipsilateral (on the same side) or contralateral scalene, or supraclavicular lymph node(s) (located above the collarbone).
Metastasis (M)
M0 No distant metastasis.
Distant metastasis.
Separate tumor nodule(s) in a contralateral (on the opposite side) lobe; tumor with pleural or pericardial nodules or malignant pleural or pericardial effusion.
Single extrathoracic (outside of the lung) metastasis in a single organ (including involvement of a single nonregional node).
Multiple extrathoracic (outside of the lung) metastases in a single organ or in multiple organs.

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original and primary source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017) published by Springer Science+Business Media.

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