Number stages for anaplastic thyroid cancer

The stage of a cancer tells you about its size and whether it has spread. Doctors use the number staging system and the TNM staging system for thyroid cancer.

There are different types of thyroid cancer. The number staging system for anaplastic thyroid cancer is different to the staging system for other types of thyroid cancer. This page is about number staging for anaplastic thyroid cancer.

The number staging system usually groups cancers into 4 groups, from stage 1 to 4.

All anaplastic thyroid cancers are considered to be stage 4 when they are diagnosed. The stage is further divided into 3 groups - 4A, 4B and 4C.

Stage 4A

Stage 4A means the cancer:

• is completely inside the thyroid gland and is any size
• hasn't spread to nearby lymph nodes or to other parts of the body.

In the TNM staging system this is the same as T1 to T3a, N0, M0.

Stage 4B

Stage 4B means different things. It can mean your cancer:

• is completely inside the thyroid gland and is any size
• has spread to nearby lymph nodes but not to other parts of the body  

In TNM staging this is the same as T1-3a, N1a, M0.

Or it can mean your cancer:

• has grown outside the thyroid into the surrounding muscles, to soft tissues in the neck such as the voice box or wind pipe (trachea), or to the nerve to the voice box, or nearby main blood vessels
• may or may not have spread to the nearby lymph nodes, but hasn't spread to other parts of the body 

In TNM staging this is the same as T3b-T4, N0 or N1a, M0.

Stage 4C

Stage 4C means your cancer has spread to other parts of the body, such as distant lymph nodes, the lungs or bones.

In TNM staging this is the same as any T, any N, M1.

Treatment

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