Table 1.

Masaoka clinical staging system.

Stage		5-year survival (%)
1	Encapsulated tumour with no gross or microscopic invasion	96–100
2	Macroscopic invasion into the mediastinal fat or pleura	86–95
3	Invasion into pericardium, great vessels or lung	56–69
4a	Pleural or pericardial metastatic spread	Up to 50
4b	Lymphatic or haematogenous spread