| Situation | Classification |
| Direct invasion of an adjacent lobe, across the fissure or directly if the fissure is incomplete | T2a# |
| Invasion of phrenic nerve | T3 |
| Paralysis of the recurrent laryngeal nerve, superior vena caval obstruction, compression of the trachea or oesophagus related to direct extension of the primary tumour | T4 |
| Paralysis of the recurrent laryngeal nerve, superior vena caval obstruction, compression of the trachea or oesophagus related to lymph node involvement | N2 |
| Involvement of great vessels: aorta, superior vena cava, inferior vena cava, main pulmonary artery (pulmonary trunk), intrapericardial portions of the right and left pulmonary artery, intrapericardial portions of the superior and inferior right and left pulmonary veins | T4 |
| Pancoast tumours with evidence of invasion of the vertebral body or spinal canal, encasement of the subclavian vessels, or unequivocal involvement of the superior branches of the brachial plexus (C8 or above) | T4 |
| Pancoast tumours without the above criteria for T4 classification | T3 |
| Direct extension to parietal pericardium | T3 |
| Direct extension to visceral pericardium | T4 |
| Tumour extending to rib | T3 |
| Invasion into hilar fat | T2a# |
| Invasion into mediastinal fat | T4 |
| Discontinuous tumour nodules in the ipsilateral parietal or visceral pleura | M1a |
| Discontinuous tumour nodules outside the parietal pleura in the chest wall or in the diaphragm | M1b |
#: Unless other criteria assign a higher T.