Stages of thyroid cancer
Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size of the tumour, which parts of the organ have cancer, whether the cancer has spread from where it first started and where the cancer has spread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).
The most common staging system for thyroid cancer is the TNM system. For most thyroid cancers there are 4 stages. Often the stages 1 to 4 are written as the Roman numerals I, II, III and IV. Generally, the higher the stage number, the more the cancer has spread. Talk to your doctor if you have questions about staging.
When describing the stage, doctors may use the words local, regional or distant. Local means that the cancer is only in the thyroid and has not spread to other parts of the body. Regional means close to the thyroid or around it. Distant means in a part of the body farther from the thyroid. The staging is different for different types of thyroid cancer. Differentiated (papillary or follicular) thyroid cancer, anaplastic thyroid cancer and medullary thyroid cancer each have their own staging. Papillary or follicular thyroid cancer is also classified into risk groups to help doctors plan treatment and follow-up.
Papillary or follicular thyroid cancer
Staging for papillary or follicular thyroid cancer depends on the age of the person when diagnosed.
Younger than 55 years of age
People younger than 55 years of age when diagnosed will have either stage 1 or stage 2 papillary or follicular thyroid cancer.
Stage 1
The tumour may have grown into nearby tissues or the cancer may have spread to nearby lymph nodes.
Stage 2
The cancer has spread to other parts of the body (called distant metastasis), such as to the lungs, liver or bone. This is also called metastatic thyroid cancer.
Age 55 and older
People 55 years of age and older when diagnosed will be given a stage from 1 to 4 for papillary or follicular thyroid cancer.
Stage 1
The tumour is only in the thyroid and is no larger than 4 cm.
Stage 2
The tumour is larger than 4 cm and may have grown into nearby muscles in the neck.
OR
The cancer has spread to nearby lymph nodes. The tumour is any size and may have grown into nearby muscles in the neck.
Stage 3
The tumour has grown into any of the following:
- soft tissue beneath the skin
- voice box (larynx)
- windpipe (trachea)
- esophagus
- a nerve to the larynx (called the recurrent laryngeal nerve)
The cancer may also have spread to nearby lymph nodes.
Stage 4A
The tumour has grown into the connective tissue in front of the spine (prevertebral fascia), into blood vessels in the space between the lungs (mediastinum), or around a carotid artery. The cancer may also have spread to nearby lymph nodes.
Stage 4B
The cancer has spread to other parts of the body (called distant metastasis), such as to the lungs, liver or bone. This is also called metastatic thyroid cancer.
Anaplastic thyroid cancer
All anaplastic thyroid cancers are stage 4 and are divided into stages 4A, 4B and 4C.
Stage 4A
The tumour is only in the thyroid.
Stage 4B
The tumour may have grown outside of the thyroid and may have spread to nearby lymph nodes.
Stage 4C
The cancer has spread to other parts of the body (called distant metastasis), such as to the lungs, liver or bone. This is also called metastatic thyroid cancer.
Medullary thyroid cancer
There are 4 stages of medullary thyroid cancer.
Stage 1
The tumour is only in the thyroid and is no larger than 2 cm.
Stage 2
The tumour is any size and may have grown into nearby muscles in the neck.
Stage 3
The cancer has spread to nearby lymph nodes in the neck in front of or around the windpipe and voice box or to lymph nodes in the space between the lungs.
Stage 4A
The cancer has spread to other nearby lymph nodes in the neck.
OR
The tumour has grown into any of the following:
- soft tissue beneath the skin
- voice box
- windpipe
- esophagus
- a nerve to the larynx
The cancer may also have spread to nearby lymph nodes.
Stage 4B
The tumour has grown into the connective tissue in front of the spine, into blood vessels in the space between the lungs, or around a carotid artery. The cancer may also have spread to nearby lymph nodes.
Stage 4C
The cancer has spread to other parts of the body (called distant metastasis), such as to the lungs, liver or bone. This is also called metastatic thyroid cancer.
Recurrent thyroid cancer
Recurrent thyroid cancer means that the cancer has come back after it has been treated. If it comes back in the same place that the cancer first started, it’s called local recurrence. If it comes back in tissues or lymph nodes close to where it first started, it’s called regional recurrence. It can also recur in another part of the body. This is called distant metastasis or distant recurrence.