lung cancer staging

Clinical Staging for Lung Cancer

• T = tumor size
• N = node involvement
• M = metastasis status

Tumor

TX:	Tumor cannot be evaluated or tumor is proven by the presence of cancer cells in the sputum or bronchial washings, but it cannot be seen during imaging or bronchoscopy ("occult" tumor)
T0:	No evidence of primary tumor
Tis:	Carcinoma in situ
T1:	Tumor 3 centimeters (< 3 cm) or less in greatest dimension, surrounded by lung or pleura, and not located in the main stem bronchus
T2:	Tumor more than 3 centimeters (> 3 cm) in greatest dimension, or tumor involving the main stem bronchus, 2 cm or more from the carina, or tumor invading the visceral pleura, or tumor with incomplete lung expansion or obstructive lung infection that does not involve the entire lung
T3:	Tumor of any size that directly invades the chest wall, diaphragm, pleura, or pericardium, or tumor that involves the main stem bronchus less than 2 centimeters (< 2 cm) from the carina (ridge between the right and left main stem bronchi), or tumor that is associated with complete lung collapse or obstructive lung infection involving the entire lung.
T4:	Tumor of any size that invades the heart, great vessels (aorta, superior or inferior vena cava, pulmonary artery, or pulmonary vein), trachea, esophagus, vertebral body, or carina, or separate tumor nodules in the same lung lobe, or tumor associated with a malignant pleural effusion.

Nodes

NX:	Regional lymph nodes cannot be assessed
N0:	Regional lymph nodes contain no metastases
N1:	Metastasis to same-side peribronchial (around the bronchi) and/or hilar (pit in the lungs where vessels enter and exit) lymph nodes and nodes within the lungs that are involved by direct spread of the primary tumor
N2:	Metastasis to same-side mediastinal and/or subcarinal (under the carina, or tracheal ridge) lymph nodes.
N3:	Metastasis to opposite-side mediastinal or hilar nodes or to same- or opposite-side scalene (neck/upper rib) or supracalvicular (above collarbone) lymph nodes.

Metastasis

MX:	Distant metastases cannot be assessed
M0:	No distant metastases are found
M1:	Distant metastases are present (this also includes separate tumor nodules in a different lobe of lung on either side).

Staging

Stage Ia:	T1, N0, M0
Stage Ib:	T2, N0, M0
Stage IIa:	N1, M0
Stage IIb:	T2, N1, M0 or T3, N0, M0
Stage IIIa:	T1-2, N2, M0 or T3, N1-2, M0
Stage IIIb:	T(any), N3, M0 or T4, N(any), M0
Stage IV:	T(any), N(any), M1

The TNM staging system is not often used for patients with small cell lung carcinoma (SCLC), because most have suspected or definite metastatic disease at the time of diagnosis. Survival in these patients usually is unaffected by minor differences in the extent of tumor involvement. Instead, most experts use a simple, two-stage system created by the Veterans Administration Lung Cancer Study Group. This system defines SCLC as being of "limited" or "extensive" stage.
Although this system has not been universally accepted, according to many experts, limited-stage SCLCs are lung cancers that are confined to one side of the chest, the mediastinum (tissues and organs of the middle chest, e.g., the heart and large vessels, windpipe), and the supraclavicular (above-collarbone) nodes. Such SCLCs can be enclosed within a tolerable radiation therapy port.
Patients with pleural effusion, very large tumors, and opposite-side supraclavicular nodes may or may not be included within this category.
Extensive-stage SCLCs are lung cancers that are too widespread to be considered limited stage. All patients with distant metastases are placed in this stage.