Cancer of the thyroid gland is rare, but increasing in incidence. Any cancer diagnosis is alarming, but thyroid cancer has a very high cure rate, and 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 and follicular thyroid cancer ('differentiated' thyroid cancer), but other less common forms of thyroid cancer are also seen. This Guide will concentrate on the ‘differentiated’ thyroid cancers as these are by far the most common and the other forms of thyroid cancer may need different ways to treat them. ’Differentiated’ means the cancer cells have similar features to normal thyroid cells.
How is thyroid cancer diagnosed?
If you notice a lump in your neck or have any other symptoms such as rapid growth of a goitre, or symptoms of a hoarse voice, or difficulty in swallowing, you should see your family doctor (GP). Not all lumps, nodules or swellings in the thyroid gland are cancerous – in fact most lumps and swellings in the thyroid gland are benign (non-cancerous). IIt is most important, though, that any lump or swelling discovered should be investigated, even if it has been there a long time. Likewise an increase in size of an existing thyroid lump needs to be investigated. Your GP will examine you, carry out thyroid blood tests and may refer you to the hospital to see a specialist for further tests.
The specialist will usually arrange an ultrasound examination and in some cases a fine needle biopsy (fine needle aspiration cytology - FNAC) to remove cells from the lump or swelling for examination under a microscope. About 19 out of 20 thyroid lumps are benign. In some cases the biopsy will show that there is thyroid cancer present. Unfortunately sometimes the biopsy does not give a definitive answer. In such cases the biopsy may have to be repeated or additional tests may be requested. In some cases the only way of knowing whether a thyroid lump is cancerous is to remove part of the thyroid gland by an operation.
What is the treatment for thyroid cancer?
That depends on the type of cancer and the stage at the time of treatment.
A lobectomy (hemithyroidectomy) alone is sufficient treatment for many small thyroid cancers while for other patients it is better to remove the whole gland. The surgeon may also remove some of the lymph nodes in the neck to check whether any cancer cells have spread. There is a small risk that surgery may affect your parathyroid glands (which control the calcium in your body) or your voice. Usually this is temporary but in some cases the change may be permanent. Ask your surgeon to explain the risks to you beforehand. National guidelines recommend that your surgery is performed by an experienced endocrine or head-and-neck surgeon who regularly does thyroid and parathyroid surgery and who is working as part of a Multi-Disciplinary Team (MDT). (See: Your Guide to Thyroid Surgery.)
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 your risk of the cancer recurring is very small. Normal thyroid cells and thyroid cancer cells are unique because they are the only cells in the body to store radioactive iodine. This means radioactive iodine can be used to treat thyroid cancer. The radiation in the iodine destroys the thyroid cells. There are small risks associated with RAI ablation, such as dry mouth, altered taste and a minimal risk of other cancers which should be discussed with you before consent. 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.
Currently there are two regimes used to prepare for RAI ablation: (1) recombinant TSH and (2) thyroid hormone withdrawal. Both approaches raise the level of TSH, which encourages the remaining thyroid cells, whether they are normal or cancerous, to take up the radioactive iodine very effectively.
Preparation Regimen 1, Recombinant TSH: after removal of your thyroid gland you will be prescribed levothyroxine (T4). 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 remain on levothyroxine throughout and therefore you will avoid the symptoms of hypothyroidism.
Preparation Regimen 2, Thyroid hormone withdrawal: after removal of your thyroid gland you will be prescribed thyroid hormone replacement. If you are due to receive RAI ablation relatively soon after your surgery, you will probably be prescribed Liothyronine (T3). 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 levothyroxine. Levothyroxine is usually stopped six weeks before RAI ablation and is replaced with T3 for four weeks before that too is stopped. The withdrawal of thyroid hormones may cause your metabolism to slow down. As a result you may experience symptoms of hypothyroidism, such as feeling cold, having dry hair and skin, constipation, tiredness, and sometimes concentration problems and mood changes. You should exercise care in using machinery and should avoid driving. Remember that this will pass and you will feel a lot better when you are back on thyroid medication.
You can increase the effectiveness of RAI ablation by following a low-iodine diet beforehand. Your hospital will provide guidelines, and there is a detailed low-iodine diet with a meal plan and recipes on the BTF website.
Radioactive iodine is taken usually as a capsule. You may well need to stay in hospital for a few days in a single room as the treatment will make you radioactive. During this time and for a short while 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 hospital will provide you with further details.
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.
Before RAI ablation, you will need to stimulate any remaining thyroid cells, whether they are normal or cancerous, to increase the uptake of radioactive iodine by raising the level of thyroid stimulating hormone (TSH).
In a few cases RAI ablation does not remove all of the thyroid cancer cells and you may need repeat treatment.
Levothyroxine (synthetic thyroxine or T4) replaces the thyroid hormone that your body would naturally produce and prevents you from being hypothyroid. Occasionally levothyroxine is required after a lobectomy. Your surgeon will do blood tests to check your thyroid levels. After a total thyroidectomy levothyroxine is always required. You will need to take this for life. The amount of levothyroxine prescribed may be slightly higher than that normally used to treat hypothyroidism (an underactive thyroid gland). This is in order 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 a short time (less than 12 months) after your treatment. You should not alter your dose without discussion with your consultant.
What kind of follow-up will I receive?
You will need to have regular check-ups long-term. These usually consist of blood tests to check your thyroid levels (TSH, T4) and to check whether there is a tumour marker called ‘thyroglobulin’ (Tg) in your blood. 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 your doctor.
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?
Subtypes of differentiated thyroid cancer
There are several less common variants of papillary and follicular thyroid cancer including Hurthle cell, tall cell, insular, and columnar.
Medullary thyroid cancer (MTC)
MTC is rare and arises in the C cells of the thyroid, which produce calcitonin. Some types of medullary thyroid cancer are associated with other endocrine abnormalities and may run in families. In genetic cases 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 removed at the time of thyroidectomy. Radioactive iodine is not used to treat MTC at all and you will not require your TSH to be kept at low levels, unlike in differentiated thyroid cancer. Follow-up is very similar to that with differentiated thyroid cancer with ultrasound scans and blood tests, but measuring calcitonin rather than thyroglobulin. Further information can be obtained from:
The Association of Multiple Endocrine Neodisplasia Disorders (AMEND): www.amend.org.uk
This is another rare and unfortunately aggressive form of thyroid cancer. It usually affects older people. Treatment may involve surgery, chemotherapy and radiotherapy.
There is also a rare condition known as a thyroid lymphoma or non-Hodgkin’s lymphoma of the thyroid, which occurs mainly in older people.
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 patients who have gone through what you may be experiencing now. Ask your doctor or hospital about support groups or contact the British Thyroid Foundation.
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 a few cases, the cancer does not respond well to RAI ablation. New targeted treatments, such as tyrosine kinase inhibitors, have shown promising results in clinical trials for these cancers and for advanced MTC when surgery is not possible.
Some important points….
- If you discover a lump you should see your doctor. Benign thyroid nodules and swellings are extremely common. It is important, though, to investigate any lump or swelling
- 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 may also contact the British Thyroid Foundation for further information and support, or if you have any comments about the information contained in this leaflet.
The British Thyroid Foundation
The British Thyroid Foundation is a registered charity: England and Wales No 1006391, Scotland SC046037
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
Our literature is reviewed every two years and revised if necessary.
© 2018 BRITISH THYROID FOUNDATION