TNM components and categories | Definitions |
T: Primary tumour | |
TX | Primary tumour cannot be assessed; or tumour proven by the presence of malignant cells in sputum or bronchial washings but not visualised by imaging or bronchoscopy |
T0 | No evidence of primary tumour |
Tis | Carcinoma in situ |
T1 | Tumour ≤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 the main bronchus)# |
T1a | Tumour ≤2 cm in greatest dimension |
T1b | Tumour >2 cm but ≤3 cm in greatest dimension |
T2 | Tumour >3 cm but ≤7 cm or tumour with any of the following features (T2 tumours with these features are classified T2a if ≤5 cm): |
Involves main bronchus, ≥ 2 cm distal to the carina | |
Invades visceral pleura | |
Associated with atelectasis or obstructive pneumonitis that extend to the hilar region but does not involve the entire lung | |
T2a | Tumour >3 cm but ≤5 cm in greatest dimension |
T2b | Tumour >5 cm but ≤7 cm in greatest dimension |
T3 | Tumour >7 cm or one that directly invades any of the following: chest wall (including superior sulcus tumours), diaphragm, phrenic nerve, mediastinal pleura, parietal pericardium; or tumour in the main bronchus <2 cm distal to the carina# but without involvement of the carina; or associated atelectasis or obstructive pneumonitis of the entire lung; or separate tumour nodule(s) in the same lobe |
T4 | Tumour of any size that invades any of the following: mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, oesophagus, vertebral body, carina; separate tumour nodule(s) in a different ipsilateral lobe |
N: Regional lymph nodes | |
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 nodes |
N3 | Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph node(s) |
M: Distant metastasis | |
M0 | No distant metastasis |
M1 | Distant metastasis |
M1a | Separate tumour nodule(s) in a contralateral lobe; tumour with pleural nodules or malignant pleural (or pericardial) effusion¶ |
M1b | Distant metastasis |
#: the uncommon superficial spreading tumour of any size with its invasive component limited to the bronchial wall, which may extend proximal to the main bronchus, is classified as T1a; ¶: most pleural (and pericardial) effusions with lung cancer are due to tumour. In a few patients, however, multiple cytopathologic examinations of the pleural (pericardial) fluid are negative for tumour, and the fluid is nonbloody and is not an exudate. Where these elements and clinical judgement dictate that the effusion is not related to the rumour, the effusion should be excluded as a staging element and the patient should be classified as M0.