Thyroid cancer

Expert reviewer, Dr Adam Dangoor, Consultant Medical Oncologist
Next review due June 2020

Thyroid cancer is a rare form of cancer that starts in your thyroid gland. Your thyroid gland lies at the base of your neck and produces hormones to help control how your cells and organs work.

Around 3,400 people are diagnosed with thyroid cancer each year in the UK. The chance of getting thyroid cancer increases as you get older. It’s more common in women, and women are more likely to get thyroid cancer in their 30s and 40s than men.

There are several different types of thyroid cancer. In most cases thyroid cancer can be treated. The type of treatment your doctor offers you will depend on the type of thyroid cancer you have and whether it has spread.

An image showing a diagram of the thyroid gland

The thyroid gland

Your thyroid gland lies at the front of your neck, just below your Adam’s apple. It’s made up of two lobes, each the size of half a plum, connected by a bridge of thyroid tissue.

Your thyroid is an endocrine gland, which means it makes hormones and releases them directly into your bloodstream. The main hormones produced by your thyroid gland are called T3 (triiodothyronine) and T4 (thyroxine). They help to control the speed at which your body uses energy – your metabolic rate. You may have come across conditions where the thyroid gland is overactive (hyperthyroidism) or underactive (hypothyroidism). These are common problems linked to the levels of T3 and T4 in your body.

Your thyroid gland also makes another hormone, called calcitonin. This helps to control the amount of calcium in your bloodstream.

Types of thyroid cancer

There are four main types of thyroid cancer. These are listed below.

  • Papillary thyroid cancer is the most common type and makes up about eight in 10 of all thyroid cancers. It’s usually slow growing but can sometimes spread to nearby lymph nodes. It’s most common in women and younger people.
  • Follicular thyroid cancer is less common than papillary thyroid cancer and usually affects slightly older people. It accounts for about one in 10 of all cases of thyroid cancer. It sometimes spreads to other parts of your body, such as your lungs or bones.
  • Medullary thyroid cancer is rare and affects around four out of every 100 people with thyroid cancer. It typically affects people in their 40s and 50s. It’s sometimes passed down in families.
  • Anaplastic thyroid cancer is also rare. It tends to grow more quickly than the other types and can be more difficult to treat. Around three in 100 people with thyroid cancer have this type. It’s more common in older people and women.


Because of the way they develop and are treated, the papillary and follicular types are sometimes grouped together and called ‘differentiated’ thyroid cancers.

It’s also possible to get another type of cancer, called lymphoma in your thyroid gland.

Symptoms of thyroid cancer

The main symptom of thyroid cancer is finding a painless lump in the front of your neck. It’s important to remember that lumps in the thyroid gland are quite common, and most are benign (not cancer). Only about one in 20 thyroid lumps are cancer.

Other, less common symptoms of thyroid cancer may include:

  • a cough that doesn’t go away
  • difficulty swallowing
  • breathing problems
  • a hoarse voice

However, these symptoms can also be caused by problems other than thyroid cancer. If you have any of these symptoms, contact your GP.

Diagnosis of thyroid cancer

Your GP will ask about your symptoms and examine you, including your head and neck. They might recommend a blood test to check the hormones produced by your thyroid gland.

If your GP thinks you may have a thyroid tumour, they’ll refer you to a doctor who specialises in thyroid cancer. Your specialist doctor may recommend further tests, including the following.

  • A blood sample to recheck the thyroid hormone levels in your blood and see how well your thyroid gland is working.
  • An ultrasound scan of your neck. This uses sound waves to produce an image of your thyroid. Your doctor may take a needle biopsy of the lump at the same time (see next point).
  • Needle biopsy (fine needle aspiration cytology, FNAC). Your doctor uses a small needle to remove some cells from the lump in your neck. These go to a laboratory for testing to find out if the cells are cancerous. See our FAQ below for more information about having this procedure.

If these tests show you have thyroid cancer your doctor may recommend further tests to see if it has spread. These may include the following.

  • CT scan. This uses X-rays to see the organs inside your body.
  • MRI scan. This uses magnets and radiowaves to produce images of the inside of your body.

If your doctor recommends these or other tests they’ll carefully explain what each involves. Feel free to ask any questions you have.

Treatment of thyroid cancer

The treatment of thyroid cancer depends on what type it is, whether it’s spread to other areas and your general health. You’ll have a team of doctors and other cancer specialists involved in planning your care. Your doctor will explain your options and take your wishes into account.


Surgery is the most common treatment for thyroid cancer. Your surgeon may recommend an operation to remove part of your thyroid gland (partial thyroidectomy) or all of it (total thyroidectomy). Lymph nodes near your thyroid gland may also be removed to see if they contain cancerous cells. The type of surgery you have will depend on several things including the size of the tumour (lump) and how far the cancer has spread.

You’ll have this surgery under a general anaesthetic, which means you’ll be asleep during the procedure.

Radioactive iodine treatment

Some people will need to have radioactive iodine treatment after surgery. This is a type of internal radiotherapy, which helps kill any remaining cancer cells and helps to prevent the cancer from returning. You swallow the radioactive iodine as a drink or capsule. Wherever they are in your body, thyroid cancer cells take in the iodine and the radiation kills them.

This treatment is given in hospital and you may need to stay there for a few days in a separate room to others. This is because you’ll remain slightly radioactive for a few days after the treatment and should limit the time you spend with other people.

Your doctor may also offer you radioactive iodine treatment if your cancer has spread and can’t be removed by surgery. But this will depend on whether or not your tumour is found to take up the radioactive iodine.

External beam radiotherapy

In external beam radiotherapy, a beam of radiation is targeted on the cancerous cells to kill them and shrink the tumour. It’s not used as often as radioactive iodine to treat thyroid cancer.

External beam radiotherapy can be used to:

  • treat anaplastic thyroid cancer that can’t be removed with surgery (see our section on types of thyroid cancer above)
  • reduce the chance of cancer coming back after surgery if radioactive iodine treatment isn’t suitable or doesn’t work
  • treat cancer that has come back after it was first treated
  • control symptoms if the cancer can’t be removed

Thyroid hormone therapy

If you’ve had surgery for thyroid cancer, your doctor may recommend that you take thyroid hormone replacement tablets (levothyroxine). As well as providing your body with the thyroid hormone it needs for health, this can be an important part of your treatment. It stops your body making another hormone, TSH (thyroid stimulating hormone). TSH may encourage cancer cells to grow.

Chemotherapy medicines

Chemotherapy uses medicines to destroy cancer cells. It’s not often used to treat thyroid cancer but may be used if the cancer has spread or comes back after other treatment.

Targeted therapy

If you have medullary thyroid cancer that can’t be removed by surgery, your doctor may offer you a targeted (or ‘biological’) therapy. These are medicines which can stimulate the body to attack or control cancer cells. You may be offered one of two medicines – vandetanib or cabozantinib. These medicines may only be available in the UK as part of a clinical trial.

After treatment for thyroid cancer

Replacement thyroid hormones

If you’ve had treatment for thyroid cancer or surgery to remove your thyroid gland, you’ll need to take hormone replacement medicine (levothyroxine). This is to replace the hormones that would have naturally been in your body if your thyroid gland was working normally.

It’s important to take the hormone replacement regularly. Without it you’ll develop symptoms of an underactive thyroid gland. These symptoms include gaining weight and feeling cold and tired. You’ll need to take this hormone replacement for the rest of your life. And you’ll need to have regular check-ups with your GP to make sure you’re receiving the right amount of hormones.

It’s important to read the patient information leaflet that comes with your medicine carefully. If you have any questions about taking your medicines you can ask your pharmacist.

Follow up after treatment

After your treatment for thyroid cancer you’ll need to have regular tests and check-ups, possibly for several years. These will check that the thyroid cancer has been treated successfully and hasn’t returned.

Your doctor will examine you, and may recommend the following tests.

  • Blood tests for the level of thyroid hormones in your body.
  • A special blood test for substances that may go up if your cancer comes back, called tumour markers. These include thyroglobulin and calcitonin.
  • An ultrasound scan of your neck to make sure the cancer hasn’t come back.
  • A radioactive iodine scan. This scans your whole body to check that your treatment killed all the cancer cells.
  • Further scans including a PET-CT scan. This combines a CT scan with a PET (positron emission tomography) scan. In a PET scan a special medicine is used to show up parts of your body where cells are extremely active. These may be cancer cells.

You won’t have all these tests at every visit. How frequent your follow up appointments are will depend on your own individual circumstances. They should gradually get less frequent as time goes by.

The appointments with your doctor are a chance for you to discuss any concerns and ask any questions you have following your treatment.

Causes of thyroid cancer

Doctor’s don’t yet fully understand what causes thyroid cancer. However, the following things may increase your risk of developing it.

  • Exposure to radiation, particularly if this was at a young age. This includes both accidental exposure and medical exposure (radiotherapy).
  • Having non-cancerous thyroid disease, such as an enlarged thyroid or inflammation of your thyroid.
  • Inherited genetic conditions. These include multiple endocrine neoplasia (MEN) type 2 or a bowel condition called familial adenomatous polyposis (FAP).
  • Other people in your close family with thyroid cancer.

How cancer develops

Help and support

Being diagnosed with cancer and facing treatment can be distressing for you and your family. An important part of cancer treatment is having support to deal with the emotional aspects as well as the physical symptoms. Specialist cancer doctors and nurses are experts in providing the support you need. Talk to your doctor or nurse if you’re finding your feelings hard to cope with.

Everyone has their own way of coping. But for further support and advice you may find it helpful to contact one of the well known cancer organisations or visit their websites. They have information about most types of cancer – often in more detail than we can go into here. Some have a telephone helpline you can ring, or an online forum you can join for a chat with others in your position. There may also be local groups where you can meet other people with similar medical issues, or other carers. Your cancer team may know of some.

See our section ‘other helpful websites’ below for contact details of relevant organisations. You may also find our general cancer articles helpful.

Frequently asked questions

  • If you have a lump in your thyroid gland, your doctor may recommend you have a test called a needle biopsy. This is to see if the lump is cancer. Your doctor uses a thin needle to remove a small sample of cells and fluid from the lump. These go to the laboratory to check for cancer cells. You can go home after your test and the results are usually back within two weeks.

    The full medical term for this test is fine needle aspiration cytology (FNAC).

    If you take medicines to thin your blood your doctor may ask you to stop taking them for a short period before the procedure. They’ll tell you when.

    Your doctor will feel for the lump, and will often use ultrasound to help guide the needle to it. You may have a local anaesthetic injection to the skin first, to numb the area. However, this isn’t always needed. Talk to your doctor before the test about whether a local anaesthetic will be used.

    When the needle is in the right place, your doctor will use it to aspirate (suck out) a small sample of cells and fluid. This goes to the laboratory for examination.

    Afterwards you’ll be able to carry on with your day as usual. However, it’s best to avoid doing anything strenuous for the rest of the day. Your doctor will tell you how to look after the biopsy area and any dressing over it. They’ll also tell you what to do if you have any problems such as bleeding or swelling – but these are rare.

    Results take up to two weeks to come back. Your doctor will tell you when and how you’ll get them. It can be a worrying time waiting for cancer test results. You may be given contact details for a specialist nurse to talk to. Or if you need support, you can contact one of the organisations we list in our section ‘other helpful websites’ below.

    Sometimes the first sample doesn’t have enough cells to be able to examine properly. If so, the test will need to be repeated.

  • Your thyroid gland is close to your larynx (voice box) and vocal cords. This means the nerves supplying your voice box can sometimes get damaged during surgery to remove your thyroid gland. This may make your voice sound hoarse and weak for a few weeks or even months after the operation. You may also find it difficult to make high-pitched sounds, which can affect your singing voice. Although this may be upsetting, these changes are often only short-term.

  • The level of calcium in your blood is controlled partly by your parathyroid glands. These are small delicate glands found behind your thyroid gland. Sometimes, these glands are harmed by the operation to remove your thyroid gland.

    If your parathyroid glands aren’t working properly, your calcium levels may fall. This can cause twitching of your facial muscles and you may feel tingling in your face, fingers and toes.

    After your surgery your doctor will check your calcium levels with a blood test. If this shows that they’re low, your doctor will probably prescribe calcium supplements. They may also offer you extra vitamin D as well.

    Usually, low calcium levels are temporary and the parathyroid glands will start working again. This means you may no longer need extra calcium. By 3 months after removal of their thyroid, only one in 10 people need to still take calcium supplements.

    However, if you take calcium supplements don’t stop taking these without discussing this with your doctor first.

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Related information

    • Endocrine cancers. Oxford handbook of oncology (online). Oxford Medicine Online., published September 2015
    • Perros P, Boelaert K, Colley S, et al. British Thyroid Association guidelines for the management of thyroid cancer. Clin Endocrinol (Oxf) 2014; 81(1):1–122. doi:10.1111/cen.12515.
    • Kumar, P, Clark, M. Clinical medicine. 8th ed. Edinburgh: Saunders; 2012
    • Thyroid cancer. BMJ Best Practice., last updated 21 July 2016
    • Thyroid anatomy. Medscape., updated 24 August 2015
    • Thyroid cancer. Medscape., updated 24 April 2017
    • Papillary thyroid carcinoma. Medscape., updated 22 September 2016
    • Thyroid cancer. PatientPlus., last checked 13 November 2015
    • Hypothyroidism. PatientPlus., last checked 7 September 2015
    • Thyroid disease and surgery. PatientPlus., last checked 23 July 2015
    • Hypoparathyroidism. PatientPlus., last checked 15 July 2014
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  • Reviewed by Dr Kristina Routh, Freelance Health Editor, Bupa Health Content Team, June 2017
    Expert reviewer, Dr Adam Dangoor, Consultant Medical Oncologist
    Next review due June 2020

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