Overview
- Thyroid cancer refers to cancer that develops within the thyroid, a gland found at the front of the neck.
- The thyroid is primarily made up of two types of cells:
- Follicular cells – these produce and store the hormones T3 (triiodothyronine) and T4 (thyroxine) and the protein Tg (thyroglobulin)
- Parafollicular cells (C-cells) – these produce the hormone calcitonin, which helps control calcium levels in the body
- Thyroid cancer is often classified by the type of cell the cancer develops from and can be differentiated or undifferentiated thyroid cancers
Classification
The four types of thyroid cancer include:
- Papillary thyroid cancer – slow-growing cancer that develops from the follicular cells in the thyroid. This is the most common type of thyroid cancer, accounting for 70-80% of all thyroid cancer diagnoses
- Follicular thyroid cancer – cancer that also develops from the follicular cells in the thyroid. This accounts for 15-20% of all thyroid cancer cases and includes Hürthle cell carcinoma
- Medullary thyroid cancer – an often hereditary cancer that develops from the parafollicular cells in the thyroid. This accounts for 4-5% of all thyroid cancer diagnoses and can be associated with tumours in other glands
- Anaplastic thyroid cancer – rare fast growing cancer that develops from the follicular or parafollicular cells in the thyroid. This accounts for 1-2% of all thyroid cancer cases and typically occurs in people over the age of 60