Revised 2026

Your guide to thyroid cancer

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Content overview

What are the main types of thyroid cancer?

How is thyroid cancer diagnosed?

What is the treatment for thyroid cancer?

What kind of follow-up will I receive?

What about other types of thyroid cancer?

How will I cope?

What is the outlook?

Some important points

Cancer of the thyroid gland is rare, but it is increasing in incidence. Any cancer diagnosis is alarming, but thyroid cancer has a very high cure rate, and fortunately, most patients go on to live a full and normal life.

What are the main types of thyroid cancer?

The types of thyroid cancer that doctors see most are papillary thyroid cancer, follicular thyroid cancer and oncocytic thyroid cancer (formerly known as Hürthle cell cancer). These are referred to as ‘well–differentiated’ or ‘differentiated’ thyroid cancer. ’Differentiated’ means the cancer cells have similar features to normal thyroid cells.

This guide will concentrate on differentiated thyroid cancers as these are the most common. There are other, less common forms of thyroid cancer, such as medullary thyroid cancer and anaplastic thyroid cancer which have different treatment options. 

How is thyroid cancer diagnosed?

If you notice a lump in your neck or have other symptoms such as rapid growth of a goitre, changes in your voice (e.g. hoarseness), or difficulty in swallowing, you should see your family doctor (GP).

Not all lumps, nodules or swellings in the thyroid gland are cancer: in fact most lumps and swellings in the thyroid gland are benign (not cancer). However, it is very important that any new lump or swelling in your neck should be investigated. Also, if you notice that an existing thyroid lump has increased in size you should have it checked.

Your GP will examine you, carry out thyroid blood tests and may refer you to the hospital to see a specialist for further tests. These blood tests will not pick up whether you have thyroid cancer but they will indicate whether your thyroid is functioning properly.

In some people, a thyroid nodule that they are not aware of may be identified during a scan for another condition. Depending on the size and appearance of it, this nodule may also require further testing.

The specialist will usually arrange an ultrasound examination. In some cases you may also have a fine needle biopsy (or fine needle aspiration cytology (FNAC)) to remove cells from the lump or swelling so they can be examined under a microscope. About 19 out of 20 thyroid lumps are benign (not cancer).

In some cases, the biopsy will show there is thyroid cancer present. Sometimes the biopsy does not give a clear answer. If this happens the biopsy may have to be repeated or additional tests may be carried out. In some cases the only way of knowing whether a thyroid lump contains cancer cells is to remove part of the thyroid gland by an operation.

What is the treatment for thyroid cancer?

The most suitable treatment depends on the type of cancer and its stage at the time of treatment.

Surgery

Papillary and follicular cancers are treated by surgery, which may mean removing only the affected side of the thyroid (hemithyroidectomy or lobectomy) or removing the whole thyroid gland (total thyroidectomy). If there are concerns that the cancer cells have spread, the surgeon may also remove some of the lymph nodes or other tissue in the neck.

There is a small risk that surgery may damage your parathyroid glands (which control the calcium in your body) or the laryngeal nerves that support the muscles of your voice box. Usually, the damage is temporary but in some cases the change may be permanent. It is important that you ask your surgeon to explain the risks to you before the surgery.

National guidelines recommend that your surgery is performed by an experienced endocrine or head-and-neck surgeon who frequently does thyroid and parathyroid surgery and works as part of a Multidisciplinary Team (MDT).

If the whole of your thyroid gland is removed during surgery, you will be prescribed levothyroxine (L-T4) as a thyroid hormone replacement after surgery. You will have to take this medication every day for life.

Radioactive iodine

After surgery you may be treated with radioactive iodine, known as radioactive iodine ablation (RAI ablation). You will not be treated with RAI ablation if you still have half your thyroid in your neck, or if the risk of your cancer returning is very small. Normal thyroid cells and thyroid cancer cells are unique because they are the only cells in the body to use iodine. This means RAI ablation can be used to treat thyroid cancer with only a small risk of damage to other tissues.

The radiation in the iodine destroys any thyroid cells that may remain after the initial surgery. There are small risks of dry mouth, swollen salivary glands and altered taste but these are usually temporary and only rarely permanent. There is also a minimal risk of other cancers and you should discuss these with your specialist before you consent to treatment. After RAI ablation, patients can usually be monitored simply by an examination of the neck, blood tests and/or scans to see if the cancer is cured.

Before RAI ablation, it is necessary to stimulate any remaining thyroid cells, whether they are normal cells or cancer cells, in order to increase the uptake of radioactive iodine. This is done by raising the level of thyroid stimulating hormone (TSH). There are currently two ways to do this:

• to have an injection of a man-made TSH called recombinant TSH
• to stop taking your thyroid hormone tablets for a few weeks before treatment (thyroid hormone withdrawal)

Both approaches raise the level of TSH, which encourages the remaining thyroid cells to take up the radioactive iodine very effectively. You only have to do one of the options, and your clinical team will help you decide on the best option for you.

Recombinant TSH

Before RAI ablation you will receive two injections of recombinant human TSH (rhTSH), which is also known as Thyrogen®. Thyrogen® injections will be given into the buttock on the two consecutive days before your RAI ablation. On the third day you will go into hospital for the RAI ablation. You will continue to take levothyroxine (L-T4) throughout and therefore you will avoid the symptoms of hypothyroidism.

Thyroid hormone withdrawal

If you are due to receive RAI ablation relatively soon after your surgery, you may be prescribed liothyronine (L-T3) instead of levothyroxine (LT4). L-T3 will be stopped two weeks before the RAI ablation. If there is a longer gap between surgery and RAI ablation, then you may receive L-T4. L-T4 is usually stopped four to six weeks before RAI ablation and is replaced with L-T3 for four weeks before that is also stopped.

The withdrawal of thyroid hormones may cause your metabolism to slow down. As a result, you may experience symptoms of hypothyroidism (an underactive thyroid gland), such as feeling cold, having dry hair and skin, constipation, tiredness, concentration problems and mood changes. You should be careful if you are using machinery and should avoid driving. Remember that this will pass and you will feel a lot better when you are back on your thyroid medication. If you are struggling with these symptoms, contact your Oncology team.

To help your treatment you will also be advised to follow a low iodine diet beforehand. Your doctor, specialist nurse or Nuclear Medicine Specialist will provide guidelines for you to follow, and there are further details about a low-iodine diet on our website.

Radioactive iodine is usually taken as a capsule. You may need to stay in hospital for a few days in a single room as the treatment will make you radioactive. Sometimes it is possible to give the treatment on a day-case basis. How many days you will stay will depend on the dose of radioiodine and how quickly your body processes it.

During this time, and for a short time after you return home, you will need to take precautions to prevent exposing other people to radioactivity, such as restricting the number of visitors and the length of their stay.

Your doctor or Nuclear Medicine Specialist (such as a Nuclear Medicine Technologist), who will be your point of contact for the treatment, will provide you with further details about the restrictions you should follow. You will also have a post-therapy scan which will show where the radioiodine has concentrated in your body.

If you are pregnant you must not have radioactive iodine. After RAI ablation treatment, women should avoid conceiving for six months and men should avoid fathering children for four months.

Very occasionally RAI ablation does not remove all of the thyroid cancer cells and you may need to have a further course of treatment.

Thyroxine (levothyroxine) Levothyroxine (synthetic thyroxine or L-T4) replaces the thyroid hormone that your body would naturally produce and prevents you from becoming hypothyroid. You will need to take this for life. The amount of levothyroxine prescribed may be slightly higher than that normally used to treat hypothyroidism. This is to suppress the blood TSH level, as a high TSH can cause any remaining thyroid cells to grow. For patients who have had an excellent response to treatment, TSH suppression may only be necessary for a short time (less than 12 months) after your treatment. You should not alter your dose without discussion with your consultant. Your GP will have been informed that you are on TSH suppressive treatment and it is advised that they liaise with your consultant before altering the dose of levothyroxine.

What kind of follow-up will I receive?

The kind of follow-up you receive will be decided upon following a discussion between you and your consultant. People with low-risk cancers that have been removed surgically may not need follow-up care. If you have received surgery and RAI ablation, you will generally get regular blood tests to check your thyroid hormone levels (TSH, T4) and to check whether there is a thyroid protein called ‘thyroglobulin’ (Tg) in your blood.

Tg is only made by thyroid cells (normal and cancer cells), so it acts as a sensitive marker for any remaining normal thyroid or thyroid cancer cells in your body. You may also have an ultrasound scan and occasionally other scans may be required. If you have any unexplained symptoms between check-ups you should discuss them with the clinical team who look after you.

Occasionally, your doctor may request a radioactive iodine scan to look out for remaining thyroid cells. This is different from your radioiodine therapy. Should you need a radioactive iodine scan, it may be possible to use Thyrogen® instead of stopping the levothyroxine medication.

What about other types of thyroid cancer?

Medullary thyroid cancer (MTC)

MTC is rare and arises in the parafollicular C cells of the thyroid, which produce a hormone called calcitonin. 25% of cases of MTC are associated with other endocrine tumours that can run in families. When a genetic cause is found, there is a 50% chance of each child of an affected parent inheriting the faulty gene. Families with a history of MTC should be referred to one of the UK’s genetic counselling centres.

MTC usually requires the whole thyroid gland to be removed (total thyroidectomy). Most people also need some of the lymph nodes in the neck removed at the time of thyroidectomy. Follow-up is very similar to that with differentiated thyroid cancer with ultrasound scans and blood tests, but measuring calcitonin rather than thyroglobulin.

Neither radioactive iodine nor suppression of TSH to low levels help people with MTC, so you will not need these treatments.

For further information about MTC:

See our BTF Guide to Medullary Thyroid Cancer

The Association of Multiple Endocrine Neoplasia Disorders (AMEND)

Anaplastic cancer

This is rare and unfortunately a very aggressive form of thyroid cancer. It usually affects older people. Treatment may involve surgery, chemotherapy and radiotherapy. These cancers can be very difficult to treat.

See our BTF Guide to Anaplastic Thyroid Cancer

Thyroid lymphoma

This is a rare condition, also known as non-Hodgkin lymphoma of the thyroid, which occurs mainly in older people.

See our BTF Guide to Thyroid Lymphoma

Other rare subtypes or variants of papillary thyroid cancer 

There are some other variants of papillary thyroid cancer (PTC) which are identified by the distinct shape of the cells they are made from under a microscope. These include Tall cell, Columnar cell, Hobnail and Diffuse sclerosing variants. They behave more aggressively than classic PTC tumours and may require different treatments. The implications of these findings in any individual case can be quite variable depending on the specific features. You should discuss this further with your own medical team.

How will I cope?

Hearing that you might have cancer is a devastating experience. You may feel a whole range of emotions: shock, denial, anger, fear and uncertainty. Waiting for the test results can be very stressful. All these feelings are normal.

If you find it hard to talk about it with family and friends, you may find it helpful to talk to someone independent or to other people who have gone through what you may be experiencing now. Ask your doctor or specialist nurse about support groups or contact the British Thyroid Foundation or Butterfly Thyroid Cancer Trust.

Butterfly Thyroid Cancer Trust

Macmillan Cancer Support

What is the outlook?

The majority of thyroid cancers are treatable. The outlook for differentiated (papillary and follicular) cancer is particularly good and most patients are cured with a combination of surgery and RAI ablation, even if the cancer has spread to the lymph nodes.

In around 5-10% of patients, the cancer does not respond well to RAI ablation. New targeted treatments, such as tyrosine kinase inhibitors, may be available and appropriate to treat these cancers and advanced MTC. Your doctor will discuss with you what options may be available if your cancer becomes more advanced.

Some important points….

• If you discover a new lump in your neck or that an existing lump has increased in size, you should see your doctor.
• Benign thyroid nodules and swellings are extremely common but it is important to investigate any new lump or swelling.
• Symptoms such as a change in your voice (e.g. hoarseness) or difficulty swallowing, should also be checked by your doctor.
• Differentiated thyroid cancer can usually be treated very successfully and most patients are cured.
• After RAI ablation, women should avoid conceiving for six months and men should avoid fathering a child for four months.

Thyroid problems often run in families and if family members are unwell, they should be encouraged to discuss with their own GP whether thyroid testing is warranted.

If you have questions or concerns about your thyroid disorder, you should talk to your doctor or specialist as they will be best placed to advise you. You can also contact the British Thyroid Foundation for further information and support, or if you have any comments about the information in this leaflet.

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The British Thyroid Foundation

www.btf-thyroid.org
The British Thyroid Foundation is a registered charity: England and Wales No 1006391, Scotland SC046037

Endorsed by:

The British Thyroid Association - medical professionals encouraging the highest standards in patient care and research

The British Association of Endocrine and Thyroid Surgeons - the representative body of British surgeons who have a specialist interest in surgery of the endocrine glands (thyroid, parathyroid and adrenal)

First issued: 2008
Revised: 2011, 2015, 2018, 2023, 2026
Our literature is reviewed every two years and revised if necessary.
© 2026 BRITISH THYROID FOUNDATION