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TNM Staging

Find out about tumour, node and metastasis (TNM) staging for primary bone cancer.

Staging bone cancer

The stage of a cancer tells the doctor how big it is and whether it has spread. It helps your doctor decide which treatment you need.

The tests and scans you have to diagnose your cancer give some information about the stage.

In bone cancer, staging also takes into account how abnormal the cells look under the microscope (the grade).

There are different systems for staging bone cancer. Your doctors might use the TNM staging system. And they might use another staging system called the Enneking staging system.

Or they might use the number staging system.

The TNM system

Here is a description of the TNM staging system for primary bone cancer. TNM stands for Tumour, Node and Metastasis.

Tumour (T)

Tumour describes the size of the tumour (area of cancer). This is a simplified description of the T stage.

T (tumour) is divided into 3 stages - T1 to T3.

T1 means the tumour is 8 cm or less at its widest point.

T2 means the tumour is more than 8 cm.

T3 means a high grade tumour where there is more than one area of cancer in the same bone.

Node (N)

Node (N) describes whether the cancer has spread to the lymph nodes.

N (node) is divided into 2 stages - N0 and N1.

N0 means there are no cancer cells in lymph nodes close to the tumour.

N1 means there are cancer cells in nearby lymph nodes.

Metastasis (M)

Metastasis (M) describes whether the cancer has spread to a different part of the body.

M (metastasis) is divided into 3 stages - M0, M1a and M1b.

M0 means the cancer has not spread to any other part of the body.

M1a means the cancer has spread to your lung.

M1b means the cancer has spread to other areas of the body apart from the lung.


The stage of your cancer helps your doctor to decide which treatment you need. Treatment also depends on:

  • your type of cancer (the type of cells the cancer started in)
  • where the cancer is 
  • other health conditions that you have

The stage of the cancer and these other factors can also give an idea of your outlook (prognosis).

Treatment might include:

  • surgery
  • radiotherapy
  • chemotherapy
  • targeted cancer drugs (biological therapy)
Last reviewed: 
22 Nov 2017
  • AJCC Cancer Staging Manual (8th Edition)
    S Edge and others
    Springer, 2016

  • Cancer and its management (7th edition)
    J Tobias and D Hochhauser
    Blackwell, 2015

  • World Health Organization classification of tumours: pathology and genetics of tumours of soft tissue and bone
    International Agency for Research on Cancer (IARC), 2002

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