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Table 3 TNM staging system for bone tumours
| T - Primary tumour | ||||
|---|---|---|---|---|
| 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 |
