The 7th lung cancer TNM classification and staging system: Review of the changes and implications

Table 3 Changes in the staging of lung cancer based on the new tumour, node, metastasis classification: Cells in the bold indicate a change from the sixth edition for a tumour, node, metastasis category[10]

Old- sixth edition- descriptor	New seventh edition-descriptor	N0	N1	N2	N3
T1 ( ≤ 2 cm)	T1a	I A	II A	III A	III B
T1 (> 2-3 cm)	T1b	I A	II A	III A	III B
T2 ( ≤ 5 cm)	T2a	I B	II A	III A	III B
T2 (> 5-7 cm)	T2b	II A	II B	III A	III B
T2 (> 7 cm)	T3	II B	III A	III A	III B
T3 (invasion)	T3	II B	III A	III A	III B
T4 (same lobe nodule)	T3	II B	III A	III A	III B
T4 (extension)	T4	III A	III A	III B	III B
M1 (ipsilateral non primary lobe nodule)	T4	III A	III A	III B	III B
T4 (pleural effusion)	M1a	IV	IV	IV	IV
M1 (contralateral lung nodule)	M1a	IV	IV	IV	IV
M1 (distant metastases)	M1b	IV	IV	IV	IV