Table 1.

Definitions and Staging System of the American Joint Committee on Cancer, 7th Edition [74]

	Primary tumour	Regional Lymph Nodes	Distant metastasis	Gradea
Stage IA	T1a	N0	M0	G1, GX
	T1b	N0	M0	G1, GX
Stage IB	T2a	N0	M0	G1, GX
	T2b	N0	M0	G1, GX
Stage IIA	T1a	N0	M0	G2, G3
	T1b	N0	M0	G2, G3
Stage IIB	T2a	N0	M0	G2
	T2b	N0	M0	G2
Stage III	T2a, T2b	N0	M0	G3
	Any T	N1	M0	Any G
Stage IV	Any T	Any N	M1	Any G

Primary Tumour (T)

TX, Primary tumour cannot be assessed

T0, No evidence of primary tumour

T1, Tumour 5 cm or less in greatest dimension*

-T1a, Superficial tumour

-T1b, Deep tumour

T2, Tumour larger than 5 cm in greatest dimension*

-T2a, Superficial tumour

-T2b, Deep tumour

*Note: Superficial tumour is located exclusively above the superficial fascia without invasion of the fascia; deep tumour is located either exclusively beneath the superficial fascia, superficial to the fascia with invasion of or through the fascia, or both superficial to and beneath the fascia

Regional Lymph Nodes (N)

NX, Regional lymph nodes cannot be assessed

N0, No regional lymph node metastasis

N1**, Regional lymph node metastasis

**Note: Presence of positive nodes (N1) in M0 tumours is considered Stage III

Distant Metastasis (M)

M0, No distant metastasis

M1, Distant metastasis

^aSee Table 2 for explanation FNCLCC grading system