Thyroid Cancer Explained

The thyroid is a butterfly-shaped gland. It has two lobes and a joining section called the isthmus.  The thyroid gland lies at the front of the neck just below the larynx (voice box) and on top of the central trachea (windpipe).

The thyroid gland has a tendency towards creating nodules, most of which are benign (non-cancerous). The American Association of Clinical Endocrinologists (AACE) encourages people to periodically perform a simple self-exam they call the Thyroid Neck Check, to check for nodules.

All nodules need to be assessed by a physician and those that are bigger than 1 or 1.5 cm should be biopsied by Fine Needle Aspiration (FNA) to determine if they are cancerous or not (a biopsy is an examination of cells under a microscope).  About 95% of thyroid nodules are not cancerous.

Thyroid cancer occurs when some of the cells that make up the gland mutate and become cancerous.  A cluster of cancerous cells may become apparent when they multiply in number and form a nodule or tumour.  Thyroid cancer is normally slow growing and it may take many years to reach the nodule stage, and some time further to become apparent to the patient and his/her physician by palpation (feeling the gland).  Sometimes patients become aware of other symptoms such as a hoarse throat or a feeling of fullness in the neck.

The primary function of the thyroid gland is to make thyroid hormones. The hormones are known as thyroxine (T4) and triiodothyronine (T3).  These are vital hormones that help control functions in your body such as metabolism, heart rate, blood pressure and body temperature.  The hormones are also related to the functioning of the heart, lungs and brain.  Patients who’ve had surgery to remove their thyroid gland, take a synthetic version of T4 as a daily pill.  (Synthroid and Eltroxin are the brand names of levothyroxine [L-T4] in Canada). The body makes use of the L-T4 and converts most of it to T3. 

To learn more about the types of thyroid cancer, and their treatment click here.