Thyroid Cancer Stages

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Thyroid Cancer Stages

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After you are diagnosed with thyroid cancer, you will have tests to determine the type of cancer cells you have and whether cancer has spread (metastasized) to other parts of your body.

Staging for thyroid cancer is based on the size of the cancer, lymph node involvement, and the involvement of underlying structures, such as muscle or bone. Staging of thyroid cancer has been classified by the American Joint Committee on Cancer (AJCC).1

  • TX: Primary tumour cannot be assessed.
  • T0: No evidence of primary tumour.
  • T1: Tumour is 2 cm (0.8 in.) or smaller and limited to the thyroid.
  • T1a: Tumour is 1 cm (0 in.) or smaller and limited to the thyroid.
  • T1b: Tumour is larger than 1 cm (0 in.) but not larger than 2 cm (1 in.) and limited to the thyroid.
  • T2: Tumour is larger than 2 cm (0.8 in.) but not larger than 4 cm (2 in.) and limited to the thyroid.
  • T3: Tumour is larger than 4 cm (2 in.) and limited to the thyroid or a tumour of any size that has spread just outside the thyroid.
  • T4a: Moderately advanced disease. Tumour of any size extending beyond the thyroid to involve soft tissues beneath the skin, the larynx, trachea, esophagus, or recurrent laryngeal nerve.
  • T4b: Very advanced disease. Tumour extends into the pre-vertebral fascia or around the carotid artery or mediastinal vessels.

All anaplastic cancers are considered T4 tumours:

  • T4a: Intrathyroidal anaplastic cancer.
  • T4b: Anaplastic cancer that has gross extrathyroid extension.

After the tumour (T) is staged, the TNM system stages lymph node involvement (N) to help determine the treatment options at each stage. The nearby (regional) lymph nodes are the central compartment, the lateral cervical, and the upper mediastinal lymph nodes. Lymph node involvement is staged in the following way:

  • NX: Nearby lymph nodes cannot be assessed.
  • N0: Cancer has not spread (metastasized) to the nearby lymph nodes.
  • N1: Cancer has spread to nearby lymph nodes.
  • N1a: Cancer has spread to Level VI, which includes the pretracheal, paratracheal, and prelaryngeal/Delphian lymph nodes.
  • N1b: Cancer has spread to the lymph nodes on one side, both sides, or opposite sides of the cervical (Levels I, II, III, IV, or V) or retropharyngeal or superior mediastinal lymph nodes (Level VII).

The last part is to determine whether cancer has spread to other parts of the body (metastasized). The TNM system stages metastasis (M) in the following way:

  • M0: Cancer has not metastasized.
  • M1: Cancer has metastasized.

The TNM staging system allows your doctor to recommend the most effective treatment options and discuss your long-term outcome (prognosis) based on the type of tumour, the stage of the cancer, your age, and your overall health.

The stage groupings are separate for papillary or follicular cancer, medullary cancer, and anaplastic cancer.

Stages of thyroid cancer
Cell type Stage TNM class
Papillary and follicular

I

Younger than 45:

  • Any T, Any N, M0

45 years and older:

  • T1, N0, M0

II

Younger than 45:

  • Any T, Any N, M1

45 years and older:

  • T2, N0, M0

III

45 and older:

  • T3, N0, M0
  • T1, N1a, M0
  • T2, N1a, M0
  • T3, N1a, M0

IVA

45 and older:

  • T4a, N0, M0
  • T4a, N1a, M0
  • T1, N1b, M0
  • T2, N1b, M0
  • T3, N1b, M0
  • T4a, N1b, M0

IVB

45 and older:

  • T4b, Any N, M0

IVC

45 and older:

  • Any T, Any N, M1
Medullary

I

  • T1, N0, M0

II

  • T2, N0, M0
  • T3, N0, M0

III

  • T1, N1a, M0
  • T2, N1a, M0
  • T3, N1a, M0

IVA

  • T4a, N0, M0
  • T4a, N1a, M0
  • T1, N1b, M0
  • T2, N1b, M0
  • T3, N1b, M0
  • T4a, N1b, M0

IVB

  • T4b, Any N, M0

IVC

  • Any T, Any N, M1
Anaplastic (all anaplastic cancers are considered Stage IV)

IVA

  • T4a, Any N, M0

IVB

  • T4b, Any N, M0

IVC

  • Any T, Any N, M1

Related Information

References

Citations

  1. American Joint Committee on Cancer (2010). Thyroid. In AJCC Cancer Staging Manual, 7th ed., pp. 87–96. New York: Springer.

Credits

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Matthew I. Kim, MD - Endocrinology
Specialist Medical Reviewer Donald Sproule, MD, CM, CCFP, FCFP - Family Medicine
Last Revised November 10, 2010

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