Table 3 TNM staging system for bone tumours

TX

Primary tumour cannot be assessed

T0

No evidence of primary tumour

T1

Tumour 8 cm or less in greatest dimension

T2

Tumour more than 8 cm in greatest dimension

T3

Discontinuous tumours in the primary bone site

N - Regional lymph nodes

NX

Regional lymph nodes cannot be assessed

N0

No regional lymph node metastasis

N1

Regional lymph node metastasis

M - Distant metastasis

MX

Distant metastasis cannot be assessed

M0

No distant metastasis

M1

Distant metastasis

M1a

Lung

M1b

Other distant sites

G - Histologic grade

GX

Grade cannot be assessed

G1

Well differentiated - low grade

G2

Moderately differentiated - low grade

G3

Poorly differentiated - high grade

G4

Undifferentiated - high grade*

Stage grouping

Stage

Tumour (T)

Node (N)

Metastasis (M)

Grade (G)

Stage IA

T1

NO

MO

G1, 2 low grade

Stage IB

T2

NO

MO

G1, 2 low grade

Stage IIA

T1

NO

MO

G3, 4 high grade

Stage IIB

T2

N0

MO

G3, 4 high grade

Stage III

T3

NO

MO

Any G

Stage IVA

Any T

NO

M1a

Any G

Stage IVB

Any T

N1

Any M

Any G

Any T

Any N

M1b

Any G