Staging thyroid cancer

Generally thyroid cancer is divided into four stages that range from small and localised, to cancer that has spread to other parts of the body. If the cancer has spread to distant parts of the body this is known as secondary (metastatic) cancer.

TNM staging Back to top

There are different ways of staging cancers. The most common staging system is the TNM system:

T describes the size of the tumour and whether it has spread into nearby tissues. There are four levels describing the tumour. It ranges from T1 where the tumour is less than 2cm and contained within the thyroid gland, to T4 where the tumour is of any size and has spread to nearby tissues.

N describes whether the cancer has spread to the lymph nodes close to the thyroid gland. There are two levels – either the lymph nodes are not affected, or the cancer has spread to lymph nodes close to the gland or in the neck or chest area.

M describes whether or not the cancer has spread to other parts of the body, such as the lungs or the bones (metastatic or secondary cancer).

Number stages Back to top

Doctors often combine the information about the tumour, the lymph nodes and whether the cancer has spread, into stage groups. Unlike most cancers, thyroid cancer is also staged according to the different types and the age of the person.

The staging of thyroid cancer can appear complicated, so it might help to get your doctor or nurse to explain the type and stage for you. 

Papillary and follicular thyroid cancer in people under 45

Stage 1 The cancer can be of any size and nearby lymph nodes may also be affected, but the cancer has not spread to other parts of the body.

Stage 2 A tumour of any size that has spread to other parts of the body, such as the bones or lungs.

There is no stage 3 or 4 for these patients.  

Papillary or follicular thyroid cancer for people aged 45 and over

Stage 1 The tumour is no bigger than 2cm in size and is contained within the thyroid gland. There has been no spread to either the lymph nodes or to other parts of the body.

Stage 2 The tumour is contained within the thyroid gland and is between 2 and 4cm in size. There has been no spread of the cancer to lymph nodes or to other parts of the body. 

Stage 3 The tumour is bigger than 4cm in size and has begun to spread outside the thyroid gland.

Or, the tumour is of any size and has spread just outside the thyroid gland. It has spread to nearby lymph nodes in the neck but not to other parts of the body. 

Stage 4A The tumour may be any size and has spread into surrounding parts of the neck (such as the muscles, nerves or blood vessels). It may have spread to the lymph nodes, but has not affected other parts of the body.

Or, the tumour is of any size and may have spread just outside the thyroid gland. It has spread to lymph nodes in the neck away from the thyroid or in the upper chest. The cancer has not spread to other parts of the body. 

Stage 4B The tumour may be any size and has spread to neck tissues near the spine or into nearby large blood vessels. The cancer may also have spread to lymph nodes, but has not spread to other parts of the body.

Stage 4C The cancer has spread to other parts of the body, such as the lung or bone. 

Medullary thyroid cancer

Stage 1 The tumour is no bigger than 2cm in size and is contained within the thyroid gland. There has been no spread to either the lymph nodes or other parts of the body. 

Stage 2 The tumour is contained within the thyroid gland and is between 2 and 4cm in size. There has been no spread of the cancer to lymph nodes or to other parts of the body.

Or, the tumour is bigger than 4cm in size and has begun to spread outside the thyroid gland. 

Stage 3 The tumour is of any size and may have spread just outside the thyroid gland. It has spread to lymph nodes close to the thyroid, but not to other parts of the body. 

Stage 4A The tumour may be any size and has spread into surrounding parts of the neck (such as the muscles, nerves or blood vessels). It may have spread to the lymph nodes, but has not spread to other parts of the body.

Or, the tumour is of any size and may have spread just outside the thyroid gland. It has spread to lymph nodes in the neck away from the thyroid or in the upper chest but not to other parts of the body. 

Stage 4B The tumour may be any size and has spread to neck tissues near the spine or into nearby large blood vessels. The cancer may also have spread to lymph nodes, but not to other parts of the body.

Stage 4C The cancer has spread to other parts of the body, such as the lung or bone.  

Anaplastic cancer

Everyone with anaplastic cancer of the thyroid is considered to be at stage 4. This stage is divided into three, depending upon how far the cancer has spread and whether it can be removed with surgery. 

Stage 4A The tumour is any size and contained within the thyroid gland. It can be removed with surgery (resectable).

Lymph nodes may also be affected, but the cancer has not spread to other parts of the body. 

Stage 4B The tumour is any size and it has begun to affect the soft tissues of the neck. It can’t be removed by surgery. Lymph nodes may also be affected, but the cancer has not spread to other parts of the body. 

Stage 4C The cancer has spread to other parts of the body, such as the lung or bones.