| IV | Any T, Any N, M1a OR Any T, Any N, M1b | TX = Primary tumor cannot be assessed, or tumor proven by the presence of malignant cells in sputum or bronchial washings but not visualized by imaging or bronchoscopy. | |
| T0 = No evidence of primary tumor. |
| Tis = Carcinoma in situ. |
| T1 = Tumor ≤3 cm in greatest dimension, surrounded by lung or visceral pleura, without bronchoscopic evidence of invasion more proximal than the lobar bronchus (i.e., not in the main bronchus).b |
| T2 = Tumor >3 cm but ≤7 cm in greatest dimension, or tumor with any of the following features (T2 tumors with these features are classified T2a if ≤5 cm): involves main bronchus, ≥2 cm distal to the carina; invades visceral pleura (PL1 or PL2); or is associated with atelectasis or obstructive pneumonitis that extends to the hilar region but does not involve the entire lung. |
| T3 = Tumor >7 cm or one that directly invades any of the following: parietal pleural (PL3) chest wall (including superior sulcus tumors), diaphragm, phrenic nerve, mediastinal pleura, or parietal pericardium or tumor in the main bronchus (<2 cm distal to the carinab but without involvement of the carina) or associated atelectasis or obstructive pneumonitis of the entire lung or separate tumor nodule(s) in the same lobe. |
| T4 = Tumor of any size that invades any of the following: mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, carina, or separate tumor nodule(s) in a different ipsilateral lobe. |
| NX = Regional lymph nodes cannot be assessed. |
| N0 = No regional lymph node metastasis. |
| N1 = Metastasis in ipsilateral peribronchial and/or ipsilateral hilar lymph nodes and intrapulmonary nodes, including involvement by direct extension. |
| N2 = Metastasis in ipsilateral mediastinal and/or subcarinal lymph node(s). |
| N3 = Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph node(s). |
| M0 = No distant metastasis. |
| M1 = Distant metastasis. |
| M1a = Separate tumor nodule(s) in a contralateral lobe tumor with pleural nodules or malignant pleural (or pericardial) effusion.c |
| M1b = Distant metastasis (in extrathoracic organs). |