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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.

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 from A to C.

Stage 4A

Stage 4A means the tumour is any size and inside the thyroid gland. It hasn't spread to nearby lymph nodes Open a glossary item or to other parts of the body.

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

Stage 4B

Stage 4B means one of the following:

  • the tumour hasn't grown outside the thyroid gland. It has spread to nearby lymph nodes but not to other parts of the body. In TNM staging this is the same as T1-3a, N1, M0.
  • the tumour has grown outside the thyroid into the surrounding strap muscles. It might have spread to the lymph nodes but not to other parts of the body. In TNM staging this is the same as T3b, any N, M0.
  • the tumour has grown outside the thyroid to soft tissues in the neck such as the voice box or wind pipe (trachea), or the nerve to the voice box, or nearby main blood vessels. It might have spread to the nearby lymph nodes but not to other parts of the body. In TNM staging this is the same as T4, any N, M0.

Stage 4C

Stage 4C means the 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
Last reviewed: 
13 Apr 2021
Next review due: 
15 Apr 2024
  • AJCC Cancer Staging Manual (8th edition)
    American Joint Committee on Cancer
    Springer, 2017

  • Thyroid cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow up
    S Filetti and others
    Annals of Oncology, 2019. Volume 30. Pages 1856-1883