Stages of thyroid cancer

Once thyroid cancer is found (diagnosed), more tests will be done to find out if cancer cells have spread to other parts of the body. This is called staging. A doctor needs to know the stage of the disease to plan treatment.

Papillary and follicular thyroid cancer

The following stages are used for papillary and follicular thyroid cancer:

STAGE I

• In patients younger than 45 years, cancer may have spread within the neck or upper chest and/or to nearby lymph nodes but not to other parts of the body.
• In patients aged 45 years and older, the tumor is 2 centimeters (about ¾ inch) or smaller and in the thyroid only.

STAGE II

• In patients younger than 45 years, the cancer has spread to distant parts of the body, such as the lung or bone, and may have spread to nearby lymph nodes.
• In patients aged 45 years and older, the tumor is larger than 2 centimeters but not larger than 4 centimeters (between ¾ and 1½ inches) in the thyroid only.

STAGE III

The cancer is found in patients aged 45 years or older. The tumor either:

• is larger than 4 centimeters; or
• may be any size and has spread just outside the thyroid and/or to lymph nodes in the neck.

STAGE IVA

The cancer is found in patients aged 45 years or older. The tumor may be any size and has spread within the neck and/or to lymph nodes in the neck or upper chest.

STAGE IVB

The cancer is found in patients aged 45 years or older. The tumor may be any size and has spread to neck tissues near the backbone or around blood vessels in the neck or upper chest. Cancer may have spread to lymph nodes.

STAGE IVC

The cancer has spread to other parts of the body, such as the lung or bone, and may have spread to nearby lymph nodes.

Medullary thyroid cancer

The following stages are used for medullary thyroid cancer:

STAGE 0 (CARCINOMA IN SITU)

No tumor is found in the thyroid but abnormal cells are found by screening tests. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is also called carcinoma in situ.

STAGE I

Cancer has formed and is 2 centimeters or smaller and in the thyroid only.

STAGE II

The tumor is larger than 2 centimeters but not larger than 4 centimeters and is in the thyroid only.

STAGE III

The tumor either:

• is larger than 4 centimeters; or
• may be any size and has spread just outside the thyroid and/or to lymph nodes in the neck.

STAGE IVA

The tumor may be any size and has spread within the neck and/or to lymph nodes in the neck or upper chest.