Thyroid cancer refers to cancer that develops within the thyroid, a gland found at the front of the neck. The thyroid produces hormones that help control certain processes in the body such as heart rate, digestion, body temperature and weight.
The thyroid is primarily made up of two types of cells:
- Follicular cells – these produce and store the hormones T3 and T4 and the protein thyroglobulin (Tg)
- Parafollicular cells (C-cells) – these produce the hormone calcitonin, which helps control calcium levels in the body
Thyroid cancer is often differentiated by the type of cell the cancer develops from.
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
Thyroid cancer is the ninth most common cancer in Australia, with 3 616 new cases in 2019 (971 new cases in men and 2 645 new cases in women).
Thyroid cancer can appear at any age. Thyroid cancers are three times more frequently diagnosed in women than men. It is the seventh most common cancer affecting Australian women of all ages, and the most common cancer diagnosed in women aged 20 to 24-years-old (the vast majority of them papillary thyroid cancers).