Thyroid cancer is cancer that affects the thyroid gland, a small gland at the base of the neck.
The most common symptom of cancer of the thyroid is a painless lump or swelling that develops in the neck.
Other symptoms only tend to occur after the condition has reached an advanced stage, and may include:
- unexplained hoarseness that lasts for more than a few weeks
- a sore throat or difficulty swallowing that doesn’t get better
- a lump elsewhere in your neck
It’s important to remember that if you have a lump in your thyroid gland, it doesn’t necessarily mean you have thyroid cancer. About 1 in 20 thyroid lumps are cancerous.
The Thyroid Gland
The thyroid gland consists of two lobes located on either side of the windpipe. Its main purpose is to release hormones (chemicals that have powerful effects on many different functions of the body).
The thyroid gland releases three separate hormones:
The T3 and T4 hormones help regulate the body’s metabolic rate (the rate at which the various processes in the body work, such as how quickly calories are burnt).
An excess of T3 and T4 will make you feel overactive, and you may lose weight. If you don’t have enough of these hormones, you’ll feel sluggish, and you may gain weight.
Calcitonin helps control blood calcium levels. Calcium is a mineral that performs some important functions, such as building strong bones.
Calcitonin isn’t essential for maintaining good health because your body also has other ways of controlling calcium.
Types of Thyroid Cancer
There are four main types of thyroid cancer. They are:
- Papillary carcinoma – this is the most common type, accounting for about 6 out of 10 (60%) cases; it usually affects people under the age of 40, particularly women
- Follicular carcinoma – accounts for around 3 out of 20 (15%) cases of thyroid cancer and tends to affect older adults
- Medullary thyroid carcinoma – accounts for between 5 and 8 out of every 100 diagnosed cases (5-8%); unlike the other types of thyroid cancer, medullary thyroid carcinoma can run in families
- Anaplastic thyroid carcinoma – this is the rarest and most aggressive type of thyroid cancer, accounting for less than 1 in 20 thyroid cancers; it usually affects older people over the age of 60
Papillary and follicular carcinomas are sometimes known as differentiated thyroid cancers, and they’re often treated in the same way.
What causes Thyroid Cancer?
In most cases, the cause of thyroid cancer is unknown. However, certain things can increase your chances of developing the condition.
Risk factors for thyroid cancer include:
- having a benign (non-cancerous) thyroid condition
- having a family history of thyroid cancer (in the case of medullary thyroid cancer)
- having a bowel condition known as familial adenomatous polyposis
- acromegaly – a rare condition where the body produces too much growth hormone
- having a previous benign (non-cancerous) breast condition
- weight and height
- radiation exposure
Diagnosing Thyroid Cancer
A type of blood test known as a thyroid function test will measure the hormone levels in your blood and rule out or confirm other thyroid problems.
If nothing else seems to be causing the lump in your thyroid, fine-needle aspiration cytology (FNAC) is used.
Further testing may be required if the FNAC results are inconclusive, or if more information is needed to make your treatment more effective.
Treating Thyroid Cancer
Your recommended treatment plan will depend on the type and grade of your cancer, and whether a complete cure is realistically achievable.
Differentiated thyroid cancers (DTCs) are treated using a combination of surgery to remove the thyroid gland (thyroidectomy) and a type of radiotherapy that destroys any remaining cancer cells and prevents the thyroid cancer returning.
Medullary thyroid carcinomas tend to spread faster than DTCs, so it may be necessary to remove any nearby lymph nodes, as well as your thyroid gland.