Primary tumour (T):

- TX - malignant cells in bronchial secretions, no other evidence

- Tis - carcinoma in situ

- T0 - none evident

- T1 - <3cm, in lobar or more distal airway

- T2 - >3cm, and >2cm distal to carina or any size if pleural involvement or obstructive pneumonitis extending to hilum but not all the lung

- T3 - involves the chest wall, diaphragm, mediastinal pleura, pericardium or <2cm from, but not at, carina

- T4 - involves the mediastium, heart, great vessels, trachea, oesophagus, vertebral body, carina or a malignant effusion is present

Regional nodes (N):

- N0 - none involved (after mediastinoscopy)

- N1 - peribronchial and/or ipsilateral hilum

- N2 - ipsilateral mediastinum or subcarinal

- N3 - contralateral mediastinum or hilum, scalene or supraclavicular

Distant metastases (M):

- M0 - none

- M1 - distant metastases present