The Thyroid and Parathyroid Glands

The thyroid is an endocrine gland. This means that the thyroid makes and releases hormones. The hormones released by the thyroid are triiodothyronine (T3), Thyroxine (T4) and calcitonin. In combination, these hormones  control  the  mineral  content  of the  blood and the body’s metabolic rate which in turn controls the body temperature and body fat.

In order to make the T3 and T4 hormones, the thyroid requires iodine, a chemical element found naturally in many foods. The thyroid absorbs the iodine and through several chemical reactions, produces the T3 and T4 hormones.

Adjoined to the thyroid gland are the parathyroid glands, also a type of endocrine gland. There are four parathyroid glands and these glands produce a hormone called the parathyroid hormone. This hormone controls the levels of three minerals in the bloodstream; calcium, phosphorous and magnesium. These minerals are essential ingredients in maintaining bone health.

Thyroid cancer

Cancer is a disease of the body’s cells.  The human body is made up of many different types of cells and therefore cancer is not a single disease with a single cause or treatment. There are more than 200 different types of cancer, each with their own diagnostic procedures and treatments.

Normal cells in the body divide in a uniformed and controlled way. When cells begin to grow out of control they divide and grow into a lump also known as a tumour. Tumours are either benign or malignant. Tests such as blood tests, biopsies and diagnostic investigations can all be used to determine the type of tumour.

In a benign tumour, the cells do not spread to other parts of the body and so are not cancerous. In a malignant tumour, the cancer cells have the ability to spread beyond the original area of the body.

The direct cause of thyroid cancer is still unknown, but risk factors linked to the development of thyroid cancer include:

  • Previous benign thyroid conditions: Excluding hyper - and hypo - thyroidism
  • Radiation exposure: Particularly radiation exposure as a child
  • Inherited genetic mutations: Observed only in the case of medullary thyroid cancer
  • Diet: High BMI or unbalanced diet
  • Gender: Women are more than twice as susceptible to thyroid cancer than men

There are four main types of cancer of the thyroid: Papillary (most common; 4 in 5 cases) and follicular (1 in 10 cases) thyroid cancers are known as differentiated thyroid cancer (DTC) and most of these cases are curable.

Other rarer cases are medullary (1 in 20 cases) and anaplastic cancers (1 in 100 cases). Both, but particularly in anaplastic cases, are more difficult to treat. It is also possible to have a lymphoma of the thyroid gland. Usually thyroid lymphomas are a type of non-Hodgkin lymphoma (NHL).

Apart from the anaplastic cancer and lymphoma, development of thyroid cancer is very slow. This means that it may be some years before problems start to occur. However, in most cases, the outlook is very good and many people can be cured, even in cases where the cancer has spread beyond the thyroid.