Bone

TNM 7 classification

TNM 6 classification

1. Rules for Classification

The classification applies to all primary malignant bone tumours except malignant lymphomas, multiple myeloma, surface/juxtacortical osteosarcoma, and juxtacortical chondrosarcoma. There should be histological confirmation of the disease and division of cases by histological type and grade.

The following are the procedures for assessing T, N, and M categories:

T categories. Physical examination and imaging
N categories. Physical examination and imaging
M categories. Physical examination and imaging

2. Regional Lymph Nodes

The regional lymph nodes are those appropriate to the site of the primary tumour. Regional node involvement is rare and cases in which nodal status is not assessed either clinically or pathologically could be considered N0 instead of NX or pNX.

3. TNM Clinical Classification

3.1. 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

3.2. N - Regional Lymph Nodes

NX. Regional lymph nodes cannot be assessed
N0. No regional lymph node metastasis
N1. Regional lymph node metastasis

3.3. M - Distant Metastasis

MX. Distant metastasis cannot be assessed
M0. No distant metastasis
M1. Distant metastasis
M1a. Lung
M1b. Other distant sites

4. pTNM Pathological Classification

The pT, pN, and pM categories correspond to the T, N, and M categories.

5. Histopathological Grading

Translation table for three- and four-grade systems to a two-grade (low grade vs. high grade) system

TNM two-grade system Three-grade systems Four-grade systems Low grade Grade 1 Grade 1 Grade 2 High grade Grade 2 Grade 3 Grade 3 Grade 4 Ewing sarcoma is classified as high grade.

6. Stage Grouping

Stage IA T1 N0, NX M0 Low grade Stage IB T2 N0, NX M0 Low grade Stage IIA T1 N0, NX M0 High grade Stage IIB T2 N0, NX M0 High grade Stage III T3 N0, NX M0 Any grade Stage IVA Any T N0, NX M1a Any grade Stage IVB Any T N1 Any M Any grade Any T Any N M1b Any grade

7. Summary

Bone T1 ≤8 cm T2 >8 cm T3 Discontinuous tumours in primary site N1 Regional M1a Lung M1b Other sites Low grade High grade