Cancer, thyroid

Page last reviewed: 13/07/2011

Thyroid cancer is an uncommon type of cancer. The most common (and sometimes only) symptom of thyroid cancer is the development of a painless lump or swelling in the throat.

The thyroid gland

The thyroid gland is a butterfly-shaped gland that sits at the base of the throat. It consists of two lobes that sit either side of the windpipe.

The main purpose of the thyroid gland is to release hormones, which are a type of chemical that have a powerful effect on many of the functions of the human body.

The thyroid gland release three separate hormones:

  • triiodothyronine - which is known as T3
  • thyroxine - which is known as T4
  • calcitonin

The T3 and T4 hormones help regulate the body's metabolic rate. The metabolic rate is how fast the various processes of the body work, such as how quickly the body burns calories.

Excess levels of T3 and T4 in the body would make someone to feel overactive and cause them to lose weight. Not enough T3 and T4 would make feel someone feel 'slow' and sluggish, and cause them to gain weight.

Calcitonin helps control the levels of calcium in your blood. However, calcitonin is not essential for normal health as the body uses other ways to control calcium. Calcium is a mineral that has many important functions, such as building strong bones.

How common is thyroid cancer?

Thyroid cancer is one of the rarer types of cancer, accounting for only 1% of all cancer cases in England. Each year in Ireland there are an estimated 145 new cases of thyroid cancer.

Women are two to three times more likely to develop thyroid cancer than men. This may be due to hormonal changes associated with the female reproductive system.

Most cases of thyroid cancer are diagnosed in people who are 30 to 50 years of age.

Rates of reported thyroid cases have risen by around 50% over the last 30 years across the world.

It is unclear whether this trend represents a true rise, or whether health professional are simply getting better at diagnosing cases of thyroid cancer that in the past would have been overlooked.

Types of thyroid cancer

There are four main types of thyroid cancer:

  • papillary carcinoma - this is the most common type, accounting for 4 out 5 of all cases; it usually affects people under 40 years of age, especially women
  • follicular carcinoma - this accounts for around 1 in 10 cases and tends to affects older adults
  • medullary thyroid carcinoma - this accounts for around 1 in 20 cases; unlike the other types of thyroid cancer, cases of medullary thyroid carcinoma can run in families
  • anaplastic thyroid carcinoma - this is the least common and most aggressive type of thyroid cancer, accounting for 1 in a 100 cases; most cases of anaplastic thyroid carcinoma affect older people who are between 60 to 80 years of age

In biological terms, papillary and follicular carcinomas have a lot in common so they are collectively known as differentiated thyroid cancers (DTCs).

Ionising radiation

The cause of thyroid cancer is largely unclear. The most important risk factor is exposure to ionising radiation, particularly if the exposure occurred during childhood. However, this cause accounts for a tiny minority of cases.

Ionising radiation is the more powerful type of radiation, as opposed to non-ionising radiation, which is the safer type of radiation released by devices such as mobile phones.

Most people will only experience exposure to significant amounts of ionising radiation if they undergo medical procedures such as X-rays or radiotherapy. Even then the amounts should be low enough not to pose a major risk.

However, before the link between ionising radiation and thyroid cancer was properly understood, many children were exposed to potentially dangerous levels of radiation to treat often harmless conditions, such as acne.

Historically, there are two major events that led to people being exposed to high levels of ionising radiation and a subsequent rise in thyroid cancer cases:

  • the detonation of atomic bombs over Hiroshima and Nagasaki in 1945
  • the accident at the Chernobyl nuclear reactor in Ukraine in 1986

See the Health A-Z topic about Radiation for more information.


Differentiated thyroid cancers

The outlook for the differentiated thyroid cancers (DTCs) is very good. These types of thyroid cancer tend to be both very slow growing and relatively straightforward to treat.

Treatment involves a two-step procedure:

  • surgery is used to remove most or all of the thyroid gland
  • a radioactive chemical called iodine is then used to kill off any remaining cancerous cells

Of the people with DTCs, 80-90% will live a normal lifespan.

Medullary thyroid carcinomas

The outlook for cases of medullary thyroid carcinoma is less favourable, as this type of thyroid cancer does not respond to iodine treatment so it can be difficult to remove all of the cancerous cells. However, the outlook is still a lot better than for most other types of cancer.

Survival rates for medullary thyroid carcinoma depend on what stage the cancer has advanced to when it is diagnosed (see Thyroid cancer - diagnosis for more information about the stages of thyroid cancer). If it is diagnosed in its early stages then the outlook is excellent, with almost all (97%) people living at least five years after a diagnosis.

If medullary thyroid carcinoma is only diagnosed when it has spread to other parts of the body then the outlook is poor, with only 1 in 4 people living at least five years after diagnosis.

However, the outlook for advanced medullary thyroid carcinoma may well improve in the future. A number of clinical trials ((a type of research that tests one treatment against another) looking at new types of medication known as targeted therapies have reported good result in terms of extending survival rates. For more information see Thyroid cancer - treatment.

Anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma is a very aggressive type of thyroid cancer with an extremely poor outlook. Less than 1 in 10 people will live at least five years after receiving a diagnosis, with the average survival time being eight months.

The larynx is the part of the throat that contains the vocal cords. It is used for breathing, swallowing and talking.
A disease is an illness or condition that interferes with normal body functions.

Page last reviewed: 13/07/2011

In its early stages, thyroid cancer tends to cause no or very few symptoms.

The main symptom of thyroid cancer is the appearance of a lump or swelling, which is usually painless, in the front of your throat, just below your Adam's apple. (Despite the name, women do have an Adam's apple; it is just much smaller and less noticeable than in men.)

Other symptoms of thyroid cancer only tend to occur once the condition has reached an advanced stage. These symptoms may include:

  • unexplained hoarseness
  • difficulty swallowing
  • difficulty breathing
  • pain in your neck
  • pain in your throat

When to seek medical advice

It is recommended that you should see your GP if you develop a swelling or lump in the front of your throat.

However, you should be aware that if you have a lump in front of your throat, it is unlikely to be the result of thyroid cancer. Only 1 in 20 cases of swellings or lumps in the throat that are large enough to be felt or seen are the result of thyroid cancer. Most cases are caused by non-cancerous swellings known as nodules.


A goitre is an enlarged thyroid gland. It can be enlarged because of one or more multiple swellings (nodules) within the gland.

Non-cancerous goitres are usually caused by other, less serious problems with your thyroid gland, such as:

  • your thyroid gland producing too much of the T3 and T4 hormones – this is known as having an overactive thyroid gland, or hyperthyroidism
  • your thyroid gland not producing enough of the T3 and T4 hormones – this is known as having an underactive thyroid gland or hypothyroidism

See the Health A-Z topics about Goitres, Overactive thyroid and Underactive thyroid for more information

Page last reviewed: 13/07/2011

How cancer begins

Cancer begins with an alteration to the structure of deoxyribonucleic acid (DNA) that is found in all human cells. This is known as a genetic mutation. The DNA provides the cells with a basic set of instructions, such as when to grow and when to reproduce.

The mutation in the DNA changes these instructions, so the cells keep growing. This causes them to reproduce uncontrollably, producing a lump of tissue known as a tumour.

How cancer spreads

Left untreated, cancer can grow and spread to the other parts of the body, usually through the lymphatic system.

The lymphatic system is made up of a network of vessels (channels) and glands called lymph nodes, which are distributed throughout the body, much like your blood circulation system. These glands produce many of the specialised cells needed by your immune system (the body's natural defence system against infection and illness).

Once the cancer reaches the lymphatic system, it is capable of spreading to any other part of your body, including your:

  • bones
  • blood
  • organs

The most common types of thyroid cancer, the differentiated thyroid cancers (DTCs - papillary carcinomas and follicular carcinomas), spread much slower than other types of cancer. In most cases where a DTC is diagnosed, it is usually limited to the thyroid gland, or has only spread to nearby lymph nodes.

The rarer types of thyroid cancer are more aggressive and spread faster. By the time it has been diagnosed, medullary thyroid carcinoma may have spread to lymph nodes. In the most advanced cases, it will have also spread to the bones or lungs, or both. Anaplastic cancer usually spreads to the windpipe and, in some cases, the lungs.

Risk factors for thyroid cancer

Radiation exposure

Exposure to radiation in childhood has been identified as a risk factor for thyroid cancer.

Two types of exposure that are associated with thyroid cancer have been identified.

The first type of exposure is exposure to nuclear fall-out. Nuclear fall-out is a type of radioactive waste that is released during a nuclear explosion. It can also occur when a nuclear reactor malfunctions, releasing high levels of nuclear waste into the atmosphere.

The second type of exposure is exposure to radiation that is used for medical treatments. It is thought that many of the cases of thyroid cancer that have been reported in recent years were actually caused by exposure to radiation that occurred between 1910 and 1960. At this time, the risks of radiation treatment were not properly understood. Most cases involved children who received radiation treatments to their neck.

Today there are much stricter regulations regarding the medical use of radiation to prevent the risk of people developing thyroid cancer. It is hoped that this will lead to a drop in the number of reported cases in future years.


Women are three times more likely to develop thyroid cancer than men.

It was thought that this may be due to the hormones that are released during a woman's period or during pregnancy. However, despite extensive research in this area, no evidence has been found to support this theory. The reason why women have an increased chance of developing thyroid cancer is still not understood.

Health conditions

There are a number of health conditions that increase your risk of developing thyroid cancer. These conditions are:

  • Hashimoto's thyroiditis - a common condition where the immune system attacks the thyroid gland
  • Cowden's syndrome - a rare genetic condition that causes abnormal growths to develop on your skin and inside your mouth and nose
  • thyroid adenoma - a non-cancerous growth of the thyroid gland
  • familial adenomatous polyposis - a genetic condition that causes abnormal growths in your intestine (part of the digestive system)

Occupational exposure

Research from Sweden suggests that people whose job involves exposure to solvents (a type of chemical used in manufacturing, engineering and the textile industry) have a slightly higher risk of developing thyroid cancer than the population at large.

Medullary thyroid carcinomas and genetic mutations

Inherited genetic mutations cause 1 in 4 cases of medullary thyroid carcinoma. A genetic mutation occurs when the DNA instructions that are carried in certain genes are altered. This means that some of the body's processes do not work in the normal way.

There are three types of inherited medullary thyroid carcinomas:

  • the familial medullary thyroid cancer (FMTC)
  • the multiple endocrine neoplasia (MEN) syndrome type 2A
  • the multiple endocrine neoplasia (MEN) syndrome type 2B

Cases of thyroid cancer related to the MEN2A or MEN2B mutations usually develop during childhood or as a teenager. Cases of thyroid cancer related to the FMTC mutations usually develop during adulthood.

All of the mutated genes (FMTC, MEN2A and MEN2b) are passed down through families and this is known as autosomal dominant inheritance. This means that if either of your parents has one of the mutations that causes medullary thyroid cancer, there is a 1 in 2 chance that you will also be born with the same mutation.

Because of this fact, if you have a parent with a history of medullary thyroid carcinoma, you should consider having your blood tested to determine whether you have any of the mutated genes. If the tests prove positive, it is usually recommended that you have your thyroid gland surgically removed as a precaution.


Familial is when a non-inherited disease or condition tends to affect more members of the same family, than other families in the general population.
Thyroid gland
The thyroid gland in the throat makes hormones to help control growth and metabolism (the process that turns the food we eat into energy).
Radiation therapy uses x-rays to treat disease, especially cancer.
Genes contain information that you inherit from your parents, such as eye or hair colour. They are carried by chromosomes.
If you have a deficiency it means you are lacking in a particular substance needed by the body.
The thyroid is a jointed piece or cartilage that encloses the vocal cords and forms the 'Adam's apple' in men.

Page last reviewed: 13/07/2011

If you have any of the possible symptoms of thyroid cancer, your GP will:

  • carry out a physical examination of your neck
  • ask you whether you are experiencing any associated symptoms, such as unexplained hoarseness

The next step is to check whether the swelling in your neck is caused by other problems with your thyroid. This is done by carrying out a blood test known as a thyroid function test.

Thyroid function test

The most common cause of swelling in the neck is either an overactive thyroid gland (hyperthyroidism) or an underactive thyroid gland (hypothyroidism). To confirm or rule out these conditions, a thyroid function test may be carried out.

A thyroid function test measures the amount of certain types of hormones in your blood. An excessive amount of the two hormones that are produced by the thyroid gland, thyroxine and triiodothyronine, would indicate an underlying condition that is making your thyroid gland overactive.

If your thyroid gland is underactive, another gland, known as the pituitary gland, will produce a hormone called thyroid stimulating hormone (TSH). TSH is released by your body to stimulate your thyroid gland. Therefore, a high level of TSH in your blood would indicate that your thyroid gland is underactive.

Further testing will be required if the thyroid function test reveals that your thyroid gland is working normally.

Fine-needle aspiration cytology

Fine-needle aspiration cytology (FNAC) is the next stage in diagnosing thyroid cancer. FNAC is carried out as an outpatient. This means you will not have to spend the night in hospital.

During a FNAC, a small needle will be inserted into the lump in your neck. The needle is used to remove a small sample of cells, which are then studied under a microscope. A FNAC can usually reveal whether or not any cancerous cells are present in your thyroid gland and, if they are, what type of thyroid cancer you have.

Further testing

Further testing may be recommended if the results of the FNAC are inconclusive, or if more information is required to make your treatment more effective.

These tests may include:

  • repeat FNAC combined with ultrasound scan
  • other types of scan, such as a CT or MRI scan

See the Health A-Z for more information about Ultrasound scans, CT scans and MRI scans.

However, in most cases, when it has not been possible to rule out thyroid cancer by FNAC, a thyroid operation will be required to remove the part of the thyroid gland that contains the lump or swelling.


Staging is how far the cancer has spread through the body; the higher the grade, the further it has spread. It is usually impossible to stage the tumour before the initial treatment has been completed -  that is, after surgery and radioactive iodine treatment (see below).

Thyroid cancer can be categorised using a system that is known as the TNM classification where:

  • T - indicates the size of the tumour
  • N - indicates whether the cancer has spread to nearby lymph nodes (small oval tissues that remove unwanted bacteria and particles from the body)
  • M - indicates whether the cancer has spread to other parts of the body (metastasis)

While widely used, the TNM system can sometimes be difficult for someone with little or no medical knowledge to understand. Therefore, for the sake of clarity, the rest of the article will use a staging system that is derived from TNM, where the stages of thyroid cancer are described numerically.

Staging for differentiated thyroid cancers (papillary carcinomas and follicular carcinomas) vary with age, as in older people these types of cancers tend to be more aggressive.

In cases of differentiated thyroid cancers in people under 45 years of age only two stages are used:

  • stage 1 - the cancer may have spread to other lymph nodes in the neck or head, but not to another part of the body
  • stage 2 - the cancer has spread to other parts of the body

Four stages are used in cases of differentiated thyroid cancers that occur in people over the age of 45, and also for all cases of medullary thyroid carcinoma:

  • stage 1 - the tumour is no larger than 2cm across and has not spread out of the thyroid gland
  • stage 2 - the tumour is now 2-4cm across but is still contained within the thyroid gland
  • stage 3 - the tumour has spread out of the thyroid gland into nearby lymph nodes
  • stage 4A - the tumour has spread out of the lymph nodes and into other tissues of the neck such as the muscles of the neck, or spread to the lymph nodes in the upper chest, but not to other parts of the body
  • stage 4B - the tumour has spread to the tissue near the spine, but not to other parts of the body
  • stage 4C - the tumour has spread to other parts of the body; typically the bones, lungs or both

Staging is not usually used for cases of anaplastic thyroid carcinoma because by the time it is diagnosed, the cancer will have spread to another part of the body.


Ultrasound scan
The thyroid is a jointed piece or cartilage that enclosed the vocal cords and forms the 'Adam's apple' in men.
Veins are blood vessels that carry blood from the rest of the body back to the heart.
Benign refers to a condition that should not become life-threatening. In relation to tumours, benign means not cancerous.
Anaesthetic is a drug used to either numb a part of the body (local), or to put a patient to sleep (general) during surgery.
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.  
Thyroid gland
The thyroid gland in the throat makes hormones to help control growth and metabolism (the process that turns the food we eat into energy).
A biopsy is a test that involves taking a small sample of tissue from the body so it can be examined.
Blood test
During a blood test, a sample of blood is taken from a vein using a needle, so it can be examined in a laboratory.

Page last reviewed: 13/07/2011

Cancer treatment team

All hospitals who treat thyroid cancer have multidisciplinary teams (MDTs) .

An MDT is made up of a number of different specialists. If you have thyroid cancer, you may see some or all of these people as part of your treatment.

It can be difficult to decide which treatment is best for you. Your cancer team will make recommendations that are based on reviewing your individual case, but the final decision will be yours.

Before going to hospital to discuss your treatment options, you may want to write a list of questions to ask the specialist. For example, you may want to find out what the advantages and disadvantages are of particular treatments.

Your treatment plan

Your recommended treatment plan will depend on the type and grade of your cancer, and whether your care team thinks that a complete cure is realistically achievable.

Most cases of differentiated thyroid cancers (DTCs - papillary carcinomas and follicular carcinomas) and some cases of medullary thyroid carcinomas are thought to have a good prospect of achieving a cure.

Differentiated thyroid cancers are treated by surgically removing your thyroid gland (thyroidectomy)

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. Lymph nodes are small oval tissues that remove unwanted bacteria and particles from the body.

Stage 4 medullary thyroid carcinomas are not usually curable, although it should be possible to slow the progression of the cancer and control any associated symptoms.

In most cases of anaplastic thyroid carcinoma a cure is not usually achievable. This is because by the time the condition has been diagnosed, it has usually spread to other parts of your body, such as the windpipe and lungs. Radiotherapy and chemotherapy can be used to slow the progression of anaplastic thyroid carcinoma and can help control any symptoms

More information about each of the treatment options is provided below.


In almost all cases of thyroid cancer it is necessary to remove some of your thyroid gland (a hemithyroidectomy) or all of your thyroid gland (a total thyroidectomy).

The decision whether to remove some or all of your thyroid gland will be influenced by a number of factors, including:

  • the type of thyroid cancer that you have
  • the size of the tumour
  • whether the cancer has spread beyond your thyroid gland

Your surgeon will explain to you what type of surgery is required, as well as why it is required, so that you can make an informed decision about undergoing surgery.

A thyroidectomy is carried out under a general anaesthetic (painkilling medication that makes you unconscious). The operation usually takes around two hours and will leave a small scar on your neck, but this will not be very noticeable.

For the first 24-48 hours after having thyroid surgery, you will be connected to a series of drips to provide fluids and help accelerate the healing process.

Following surgery, your neck will feel sore, so you will be given painkillers to help ease any discomfort. Your voice may sound hoarse, but this usually passes within a few weeks. In a small number of cases, the hoarseness can be permanent.

After a thyroidectomy, swallowing food may feel painful for a number of weeks. It may therefore be necessary to switch to a diet of soft food until your throat recovers from the surgery. A nurse or dietitian will be able to provide you with advice about a suitable diet plan.

Most people are well enough to leave hospital within three to five days of thyroid surgery. However, you will need to rest at home for two to three weeks and avoid any activities that could put a strain on your neck, such as heavy lifting. A member of your MDT will be able to advise you when you will be healthy and fit enough to resume normal activities and return to work.

Replacement hormone therapy

If some or all of your thyroid gland is removed, it will no longer be able to produce the hormones that regulate your metabolic system. This means you will experience the symptoms of an underactive thyroid (hypothyroidism) including:

  • fatigue (extreme tiredness)
  • weight gain
  • dry skin

To compensate for the removal of your thyroid gland, you will need to take replacement hormone tablets for the rest of your life.

If your surgery is to be followed by radioactive iodine treatment, it is likely that initially you will be given a hormone tablet known as triiodothyronine. Once radioactive iodine treatment is completed, you will be prescribed an alternative hormone tablet called thyroxine, which most people only need to take once a day.

You will require regular blood tests to check that you are receiving the right amount of hormones, or determine whether your dose needs to be adjusted.

It can take some time to achieve the optimum dose. Until that time you may experience symptoms of tiredness or weight gain if your hormone levels are too low. Alternatively, if your hormone levels are too high, you may experience symptoms of:

  • weight loss
  • hyperactivity
  • diarrhoea

Once the right dose has been determined, you should not experience any more side effects.

Calcium levels

Occasionally, the parathryoid glands can be affected during surgery. The parathryoid glands are located close to the thyroid gland, and help regulate the levels of calcium in your blood.

If your parathryoid glands are affected during surgery, you may experience a drop in calcium levels, which can cause a tingling sensation in your hands, fingers, lips and around your nose.

If you experience any of these symptoms, report them to your MDT or to your GP. You will probably be required to take calcium supplement tablets. Most people only need to take a short course of calcium supplements, as over time, the parathryoid glands will resume their normal function.

Radioactive iodine treatment

Following thyroid surgery, a course of radioactive iodine treatment is recommended. This can help destroy remaining cancer cells in your body and prevent the cancer from returning.

If you are currently taking thyroid hormone replacement tablets, you will be required to stop taking them for two to four weeks before treatment. They can interfere with the effectiveness of the iodine treatment.

After you have stopped taking your thyroid hormone replacement tablets, you may feel very tired and weak, but these symptoms will pass once you begin taking the tablets again.

If it is thought that withdrawing your hormone replacement treatment could be particularly problematic, you may be given a medicine called recombinant human thyroid stimulating hormone (rhTSH). This is an injection that is given on two consecutive days. Its main advantage is that you will not need to interrupt your thyroid hormone replacement treatment.

However, rhTSH may not be suitable for you for a number of reasons. Your MDT will be able to advise you about whether or not rhTSH is suitable for you.

The procedure

During radioactive iodine treatment, you will swallow radioactive iodine in either liquid or capsule form. The radiation that is contained in the iodine will travel up into your neck through your blood supply and destroy any cancerous cells.

Side effects of radioactive iodine treatment are uncommon, but a small number of people may experience tightness, pain or swelling in their throat and may feel flushed (warm). These side effects usually pass within 24 hours.

You may notice a change in your taste and dryness of your mouth. These symptoms usually disappear after a few weeks or months, but some people have permanent altered taste and dry mouth.

Following radioactive iodine treatment, you will need to stay in hospital for three to five days because the iodine will make your body slightly radioactive. As a precaution, you will need to stay in a single room, protected by lead sheets, so that hospital staff are protected against exposure to radiation.

Visitors will usually not be able to enter your room during this time, and pregnant women and children will not be allowed to visit because they are more vulnerable to the effects of radiation. Hospital staff members will keep their contact with you to a minimum during this time.

Your bodily fluids, such as urine, will also be slightly radioactive for three to five days, so it is important that you flush the toilet every time you use it. Your sweat will also be radioactive so you should have a bath or shower every day.

Once the radioactive levels in your body have subsided you will be allowed to return home.

Dietary recommendations

If you are receiving radioactive iodine treatment, you will be asked to eat a diet that is low in iodine because a high iodine diet can reduce the effectiveness of your treatment. It is recommended that you:

  • avoid all seafood
  • limit your consumption of dairy products
  • do not take cough medicines or use sea salt (sea salt is a coarser type of salt than table salt) as both contain iodine
  • do not eat glace and maraschino cherries, as they contain colouring (E127) that is known to be high in iodine

Eat plenty of fresh meat, fresh fruit and vegetables, and pasta and rice. They are all low in iodine.

Pregnancy and breastfeeding

You should not have radioactive iodine treatment if you are pregnant, or if there is a good chance that you may be. This is because the treatment could damage any unborn children. You should tell your MDT if you are unsure. Any treatment will need to be delayed until your pregnancy is complete.

If you are not pregnant, you will still be required to use a reliable contraceptive for at least six months after receiving your iodine treatment. This is because there is a small risk that any child conceived during this time could develop birth defects.

A similar risk applies to men, who should use a reliable contraceptive for at least four months after receiving iodine treatment.

Your MDT will be able to advise you about when it is safe for you to attempt to conceive a child.
If you are breastfeeding, you should stop for at least four weeks (but preferably eight weeks) before iodine treatment begins, and you should not resume until after your treatment has finished. It is safe to begin breastfeeding if you have another child at a future date.


Radioactive iodine treatment does not affect fertility in women, but there is a small risk that it could affect your fertility if you are a man, if you are required to undergo multiple sessions of treatment. Your MDT can advise you about the level of risk in your individual circumstances.

If the risk is significant, you may wish to consider having your sperm or eggs harvested and frozen, so that they can be used for fertility treatment at a later date. See the Health A-Z topic about Infertility for more information.

External radiotherapy

External radiotherapy, where radioactive waves are targeted at affected parts of the body, is usually only used to treat advanced, or anaplastic, thyroid carcinomas.

The length of time that you require radiotherapy for will depend on the particular type of thyroid cancer that you have and its progression.

Side effects of radiotherapy include:

  • nausea (feeling sick)
  • vomiting
  • tiredness
  • pain on swallowing
  • dry mouth

These side effects should pass two to three weeks after your radiotherapy has finished.


Chemotherapy is usually only used to treat anaplastic thyroid carcinoma that has spread to other parts of your body.

Chemotherapy involves taking medicines that kill cancerous cells. It is rarely successful at curing anaplastic cancer, but it can slow its progression and help to relieve symptoms.

Possible side effects of chemotherapy include:

  • nausea
  • vomiting
  • tiredness
  • loss of appetite
  • hair loss
  • mouth ulcers

If you are receiving chemotherapy, you will also be more vulnerable to infection. You should see your GP if you suddenly feel ill, or your temperature rises above 38C (100.4F).

  • they think that it is likely to be effective
  • if there are no better alternatives, and
  • if the benefits of treatment outweigh any associated risks


Radiation therapy uses x-rays to treat disease, especially cancer.
The thyroid is a jointed piece or cartilage that enclosed the vocal cords and forms the 'Adam's apple' in men.
Lymph nodes
Lymph nodes are small oval tissues that remove unwanted bacteria and particles from the body. Part of the immune system.
Thyroid gland
The thyroid gland in the throat makes hormones to help control growth and metabolism (the process that turns the food we eat into energy).
Dose is a measured quantity of a medicine to be taken at any one time, such as a specified amount of medication.
Anaesthetic is a drug used to either numb a part of the body (local), or to put a patient to sleep (general) during surgery.
Chemotherapy is a treatment of an illness or disease with a chemical substance, e.g. in the treatment of cancer.
Cytotoxic medicine is used to treat cancer.

Your care team

Members of your care team may include:

  • a surgeon
  • a endocrinologist (a specialist in the treatment of hormonal conditions)
  • an oncologist (a specialist in the treatment of cancer)
  • a pathologist (a specialist in diseased tissue)
  • a radiologist (a specialist in using radiotherapy to treat cancer)
  • a specialist cancer nurse, who will usually serve as the first point of contact between you and the rest of the team 

Page last reviewed: 13/07/2011

Recurring cancer

An estimated 5-20% of people with a history of thyroid cancer will experience a return of cancerous cells in their neck. An estimated 10-15% of people will experience a return of cancerous cells in other parts of their body, such as their bones. Cancerous cells can return many years after surgery and radioactive iodine treatment has been completed.

Due to this risk, you will be asked to attend regular check-ups, so that if any cancerous cells do return, they can be quickly treated.

Three routine tests can be used to check for the return of cancerous cells. They are:

  • thyroglobulin testing
  • ultrasound scan of the neck
  • a radioactive iodine scan

These are described below.

Thyroglobulin testing

Thyroglobulin is a protein that is released by a healthy thyroid gland, but it can also be released by cancerous cells.

If you have had your thyroid gland removed, there should be no thryoglobulin present in your blood, unless cancerous cells have returned.

Therefore, regularly testing your blood for thryoglobulin can be an effective way of making sure that any cancerous cells have not returned.

For the first few years after surgery, you will probably require thryoglobulin testing every six months. After this time testing will be required once a year.

'Stimulated thyroglobulin' is where a person's thyroglobulin level is tested while they are not on thyroid hormone treatment, in preparation for an iodine scan or shortly after receiving recombinant human thyroid stimulating hormone (rhTSH). The stimulated thyroglobulin test is more sensitive and therefore more valuable than a thyroglobulin test without the above preparation.

Ultrasound scan

An ultrasound scanner uses high frequency sound waves to create an image of part of the inside of the body. Ultrasound scans can be a useful way of detecting any changes or abnormalities inside your neck that could indicate the recurrence of cancer.

Ultrasound scans are increasingly being used in combination with thyroglobulin testing because research has found that it is an effective method of detecting recurring thyroid cancer.

Radioactive iodine scan

After surgery, you may also be asked to attend a radioactive iodine scanning test. This test involves swallowing a small amount of radioactive iodine before your body is scanned using a special camera. The radioactive iodine may highlight any cancerous thyroid cells that may remain in your body.

The preparation for an iodine scan is similar to having radioactive iodine treatment. You will need to go on a low iodine diet and stop taking your thyroid homrome medication. Alternatively, recombinant human thyroid stimulating hormone (rhTSH) can be used without having to interrupt your thyroid hormone medication. As the dose of radioactive iodine that is used for the scan is miniscule (very small), no precautions, such as keeping your distance from others, are required, However, if you think that you may be pregnant, or if you are breastfeeding, you must let the doctors know before your test.

A radioactive iodine scan is usually carried out six to eight months after surgery. If the test results are negative, further testing is not usually required.

Page last reviewed: 13/07/2011

Precautionary removal of the thyroid gland

If you test positive for one of the genes that is known to cause medullary cancer (see Thyroid cancer - causes), you may be advised to have your thyroid gland removed as a precaution.

If you decide to have surgery, you will need to take replacement hormones for the rest of your life. See the Thyroid Cancer - treatment for more information.


From the available evidence, eating a healthy balanced diet is the best way for you to prevent getting thyroid cancer and all other types of cancer.

A low-fat, high-fibre diet is recommended, with plenty of fresh fruit and vegetables (at least five portions a day) and wholegrains.


The thyroid is a jointed piece or cartilage that enclosed the vocal cords and forms the 'Adam's apple' in men.

Content provided by NHS Choices and adapted for Ireland by the Health A-Z.

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