About staging and grading for bone cancer

Staging means how big the cancer is and whether it has spread. Grading means how abnormal the cancer cells look under a microscope. 

Doctors use the stage and grade of bone cancer to help them decide which treatment you need. 

This page is about cancer that starts in your bone (primary bone cancer). If your cancer has spread into bone from another part of the body, it is called secondary or metastatic bone cancer.

Staging bone cancer

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).

Your doctors and surgeons might use one of 2 different systems to stage your bone cancer. These are:

• TNM staging system

• number staging system

They will explain which one they are using and what this means for you.

Staging and grading for bone cancer is complicated. The most common system doctors use is the TNM system.

Grading bone cancer

The grade of bone cancer gives your doctor a guide to how the cancer may behave.

Low grade cancers have cells that look very much like normal cells. These cancers usually grow slowly and are less likely to spread.

High grade cancers have cells that look very abnormal. These cancers generally grow more quickly and are more likely to spread.

In the TNM system, bone cancer cells are graded from GX to G3:

• grade X (GX) means the grade cannot be assessed

• grade 1 (G1) means the cells look similar to normal bone cells (low grade)

• grade 2 (G2) means the cells look quite different to normal bone cells (high grade)

• grade 3 (G3) means the cells look very different to normal bone cells (high grade)

All Ewing sarcomas are high grade (G3).

The TNM stages

TNM stands for Tumour, Node and Metastasis. The system describes:

• the size of the cancer (tumour or T)
• whether the cancer has spread to your lymph nodes (N)
• whether the cancer has spread to a different part of your body (metastasis or M)

The number stages

The tumour, node and metastasis results are put together with the grading to give the number stage. The following is a summary of the staging for bone cancer. There is no number staging for bone cancer that starts in the back (spine) and pelvis .

Stage 1A

The cancer is 8 cm or less across. It has not spread to the lymph nodes or other parts of the body. The cancer is low grade or the grade can't be assessed.

Stage 1B

The cancer is more than 8 cm across, or is in more than one place in the same bone. It has not spread to the lymph nodes or other parts of the body. The cancer is low grade or the grade can't be assessed.

Stage 2A

The cancer is 8 cm or less across. It has not spread to the lymph nodes or other parts of the body. The cancer is high grade.

Stage 2B

The cancer is more than 8 cm across. It has not spread to the lymph nodes or other parts of the body. The cancer is high grade.

Stage 3

The cancer is in more than one place in the same bone. It has not spread to the lymph nodes or other parts of the body. The cancer is high grade.

Stage 4A

The cancer is any grade and is either:

• any size 
• in more than one place in the same bone

There are no cancer cells in the lymph nodes and it has only spread to the lung.

Stage 4B

This means the cancer has spread to the lymph nodes or to parts of the body such as the liver, other bones or the brain.

Treatment

As well as the stage and grade of your bone cancer, your treatment will depend on other factors. These include:

• the type of bone cancer
• where the cancer is
• your general health and level of fitness

The main treatment for bone cancer can include:

• surgery

• radiotherapy

• chemotherapy

Some people might have a targeted cancer drug . You might have treatment as part of a clinical trial .