Thyroid cancer is a rare type of cancer that affects the thyroid gland, a small gland at the base of the neck that produces hormones.

It's most common in people in their 30s and those over the age of 60. Women are 2 to 3 times more likely to develop it than men.

Thyroid cancer is usually treatable and in many cases can be cured completely, although it can sometimes come back after treatment.

Symptoms of thyroid cancer

Symptoms of thyroid cancer can include:

• a painless lump or swelling in the front of the neck – although only 1 in 20 neck lumps are cancer
• swollen glands in the neck
• unexplained hoarseness that does not get better after a few weeks
• a sore throat that does not get better
• difficulty swallowing

Find out more about the symptoms of thyroid cancer.

When to get medical advice

See a GP if you have symptoms of thyroid cancer. The symptoms may be caused by less serious conditions, such as an enlarged thyroid (goitre), so it's important to get them checked.

A GP will examine your neck and can organise a blood test to check how well your thyroid is working.

If they think you could have cancer or they're not sure what's causing your symptoms, you'll be referred to a hospital specialist for more tests.

Find out more about how thyroid cancer is diagnosed.

Types of thyroid cancer

There are 4 main types of thyroid cancer:

• papillary carcinoma – the most common type, accounting for about 8 in 10 cases; it usually affects people under 40, particularly women
• follicular carcinoma – accounts for up to 1 in 10 cases and tends to affect middle-aged adults, particularly women
• medullary thyroid carcinoma – accounts for less than 1 in 10 cases; unlike the other types, it can run in families
• anaplastic thyroid carcinoma – the rarest and most serious type, accounting for around 1 in 50 cases; it usually affects people over the age of 60

Papillary and follicular carcinomas are sometimes known as differentiated thyroid cancers. They tend to be easier to treat than the other types.

Causes of thyroid cancer

Thyroid cancer happens when there's a change to the DNA inside thyroid cells which causes them to grow uncontrollably and produce a lump.

It's not usually clear what causes this change, but there are a number of things that can increase your risk.

These include:

• other thyroid conditions, such as an inflamed thyroid (thyroiditis) or goitre – but not an overactive thyroid or underactive thyroid
• a family history of thyroid cancer – your risk is higher if a close relative has had thyroid cancer
• radiation exposure in childhood – such as radiotherapy
• obesity
• a bowel condition called familial adenomatous polyposis (FAP)
• acromegaly – a rare condition where the body produces too much growth hormone

Treatments for thyroid cancer

Treatment for thyroid cancer depends on the type of thyroid cancer you have and how far it has spread.

The main treatments are:

• surgery – to remove part or all of the thyroid
• radioactive iodine treatment – you swallow a radioactive substance that travels through your blood and kills the cancer cells
• external radiotherapy – a machine is used to direct beams of radiation at the cancer cells to kill them
• chemotherapy and targeted therapies – medicines used to kill cancer cells

After treatment, you'll have follow-up appointments to check whether the cancer has come back.

Read more about how thyroid cancer is treated.

Outlook for thyroid cancer

Around 9 in every 10 people are alive 5 years after a diagnosis of thyroid cancer. Many of these are cured and will have a normal lifespan.

But the outlook varies depending on the type of thyroid cancer and how early it was diagnosed. At present the outlook is:

• more than 9 in 10 people with papillary carcinoma live at least 5 years after diagnosis
• more than 9 in 10 people with follicular carcinoma live at least 5 years after diagnosis
• more than 7 in 10 men, and around 9 in 10 women with medullary thyroid carcinoma live at least 5 years after diagnosis
• around 1 in 10 people with anaplastic thyroid carcinoma live at least 5 years after diagnosis

Up to 1 in 4 people treated for thyroid cancer are later diagnosed with cancer in another part of the body, such as the lungs or bones, but cancer can often be treated again if this happens.