Thyroid cancer is a rare type of cancer that affects the thyroid gland, a small gland at the base of the neck. The most common symptom of thyroid cancer is a painless lump or swelling that develops in your neck.
Where is the thyroid gland?
The thyroid gland sits in the front of the neck just below the voice box (larynx). It is made up of 2 main lobes (right and left) joined across the middle by a thinner strip called the isthmus. There is also a much smaller pyramidal lobe in some people. The gland is butterfly or bow tie shaped.
What does the thyroid gland do?
It produces thyroid hormones called thyroxine (T4) and tri-iodothyronine (T3). These hormones are very important and help control the body’s metabolism (use of energy). The thyroid gland also produces calcitonin. This helps control the amounts of calcium and phosphate salts in the body. The level of calcitonin is raised when medullary thyroid cancer is present.
How common is thyroid cancer?
Compared to breast, lung, prostate and bowel cancers thyroid cancer is much less common. In 2010, there were approximately 2654 new cases (1906 women, 748 men) diagnosed in the UK.
(Compared to breast cancer 49,961: lung cancer 42,026: bowel cancer 40,695: prostate cancer 40,975. For more information go to UK Cancer Research Stats.)
What symptoms does thyroid cancer cause?
The commonest way that thyroid cancers are found is when someone notices a lump or nodule in the neck where the thyroid gland sits. This is usually painless and many patients feel otherwise well.
It is very important to know however, that having a lump in the thyroid is quite common and most lumps are NOT thyroid cancer. In fact only about 1 person in 20 presenting with a thyroid lump will have thyroid cancer as the cause of the lump. The other lumps will be benign and hence will not contain cancer.
Other possible ways for thyroid cancer to be diagnosed include:
- Swollen lymph glands/nodes in the neck
- Unexpected finding when thyroid gland removed during an operation for another reason
Less common ways include:
- Hoarse voice
- Difficulty swallowing
- Difficulty breathing or noisy breathing
In rare cases, the first signs may be due to the cancer having spread from the thyroid gland to other parts of the body where it produces secondary tumours (metastases). For example, the lungs or bones.
Thyroid function blood tests are usually normal in thyroid cancer and a normal test does not therefore rule out the possibility of thyroid cancer being present if there is a nodule in the thyroid.
Who is at risk?
Thyroid swellings/nodules are very common but most nodules are not cancers.
Usually it is not known why a particular person has developed thyroid cancer but there are some known risk factors. These include:
- Previous exposure to radiation (for example children in Russia exposed to radiation from the Chernobyl accident, patients who may have had radiotherapy (x ray treatment) for a different type of cancer as a child or young adult)
- Family history of thyroid cancer (particularly important for medullary thyroid cancer)
There are five main thyroid cancer types:
This is the most common type and often presents in young women. However, this does not mean it cannot be found in older people, children and men. If this type of cancer spreads it often goes to the lymph glands/nodes in the neck or nearby although, like with any cancer, it can spread elsewhere.
This is the second most common type and tends to occur in a slightly older group. This type of cancer is much less likely to spread to the lymph glands and may spread to other parts of the body through the bloodstream.
If this type of cancer is diagnosed it is usual to check to see if it is the inherited type so that other family members can be offered screening blood tests to see if they are at risk and whether they need any treatment.
If a parent has the inherited form of medullary thyroid cancer there is a 50% (1 in 2) chance that each of their children could also have inherited the faulty gene.
The inherited type can also be associated with other uncommon cancers and patients may be diagnosed with MEN 2 syndrome (Multiple Endocrine Neoplasia syndrome 2). For more information go to http://www.amend.org.uk
If you have medullary cancer and are interested in participating in our project, please click here.
This is another rare type of thyroid cancer and tends to present at an older age. The majority of patients are older than 60 years. It tends to grow more quickly than the other types and can be difficult to treat.
If you have anaplastic cancer and are interested in participating in our data collection project, please click here.
The National Anaplastic Thyroid Cancer Tissue Bank and Database project (NATT) was launched in 2013. The project offers patients with this diagnosis a rare opportunity to participate in research. By collecting tissue and blood samples along with clinical information from across the UK we will be able to gather a significant amount of data which will help us make progress with research in to this difficult to treat disease. We hope to learn more about why and how this type of cancer develops so that we can then develop new ways to treat it. This is going to be a long term project which will need to run over a number of years.
Patients who are interested in taking part will be asked to provide their consent for their already collected tissue samples (e.g. thyroid gland biopsy) to be donated to NATT. They will also have the option to donate a small blood sample and to have their clinical data collected. This will be stored securely and confidentially and will only be accessible by your own doctor and the study’s chief investigator.
If you would like to find out more about NATT please contact the Chief Investigator via Laura.Moss@wales.nhs.uk or 029 20316205
Non Hodgkin’s lymphoma is another rare thyroid tumour. It is treated like lymphomas that can arise anywhere in the body rather than like the other types of thyroid cancer. The treatment in this case may involve chemotherapy (drug treatment), monoclonal antibody therapy (e.g. rituximab) and radiotherapy (x ray treatment). For further information – www.lymphoma.org
Thyroid function tests (TFTs): this test checks the level of thyroid hormones in the blood. It is usually requested whenever someone first presents to their doctor with a thyroid swelling. It is a helpful test to see if the thyroid gland is working normally. This test is usually normal if thyroid cancer is present.
Calcitonin: this test can help diagnose medullary thyroid cancer as there is a high level of this hormone in the blood in this disease. This test is not helpful for other types of thyroid cancer and is not usually done until after the tests mentioned below.
Fine needle aspiration cytology (FNAC)
This involves a small needle being inserted through the skin into the thyroid gland lump or into lymph glands/nodes in the neck to remove some cells. This can either be done in the routine clinic or may be done with the help of an ultrasound scan.
The sample of cells is then looked at with a microscope to see if there are any signs of thyroid cancer present.
The test is most useful when cancer cells can be seen. If the test does not show any cancer cells, this does not necessarily mean cancer is not present, as not all types of cancer can be diagnosed with this test. Follicular thyroid cancer cannot be diagnosed by FNAC in which case a diagnostic thyroid lobectomy (removal of the abnormal lobe) will need to be performed so that the whole thyroid nodule can be examined in the laboratory in order to reach a diagnosis.
This test may need to be repeated if the first sample is not helpful. The test may also be negative if the needle does not pick up any cancer cells.
Sometimes a FNAC result will not be helpful and a core biopsy or very occasionally a surgical biopsy may be needed. . If this is needed the doctor would explain in more detail what it would entail and whether any anaesthetic is required.
Thyroid Ultrasound scan (USS)
This test uses gel and a probe rubbed over the neck to look at the size and texture of the thyroid gland and the lymph glands/nodes in the neck. It can show if there are any lumps in the thyroid gland, if the lumps are solid or fluid containing and if the lymph glands/nodes look normal in shape and size. If anything shows up it is possible to use the ultrasound probe and pictures to guide the needle used for a FNA (see above).
CT (Computerised Tomography) or MRI (Magnetic Resonance Imaging)
These 2 types of scan show a 3 dimensional picture of the inside of the body. They are not always required but can be helpful to show if the cancer is growing outside of the thyroid gland and can provide more information on the lymph glands/nodes and other parts of the body such as the lungs, liver and bones.
Thyroid radionucleotide or radioisotope scans
This test is no longer commonly done. It involves an injection of a small amount of radioactive liquid (either iodine or technetium) into an arm vein followed by a scan about 20 minutes later. The scan pictures are taken using a gamma camera x ray machine which is positioned over the neck area.
PET (Positron Emission Tomography) scan
This is another type of radioactive scan. It is not so widely available in the UK as the other types of scan discussed above. It is rarely needed at the time of thyroid cancer diagnosis but might be useful during the follow up period of a small number of patients when other x ray tests have not been helpful.
More information on some of these x-ray (radiology) examinations can be found at www.goingfora.com/radiology
This is used to describe the size of the thyroid cancer and whether it has spread outside the thyroid gland to involve the lymph glands/nodes or other parts of the body.
The mostly commonly used staging system is called ‘TNM’. This stands for Tumour, Nodes and Metastases.
There are 4 T-stages (1-4) and this describes the size of the tumour in relation to the thyroid gland.
N describes whether the cancer has spread to the lymph nodes/glands close to the thyroid gland.
M describes whether the cancer has spread to other parts of the body, such as the lungs or bones, to produce ‘secondaries’.
Surgery is usually the first treatment needed for papillary, follicular and medullary thyroid cancers. It is unlikely to be recommended for thyroid lymphoma patients and is only occasionally suitable for patients with anaplastic thyroid cancer.
If thyroid cancer has been diagnosed before surgery it is usual for the whole thyroid gland to be removed during the operation (total thyroidectomy). If there has been difficulty diagnosing the reason for a thyroid lump or if cancer was not suspected before surgery then removal of only one lobe of the thyroid may be done (hemithyroidectomy or lobectomy).
If only one lobe has been removed and then cancer is discovered in it, it is usual to consider whether the other thyroid lobe needs to be removed at a second operation (a completion thyroidectomy). In some cases however (young patients with small follicular or papillary tumours) it might be suggested not to remove the remaining lobe.
Sometimes the lymph glands/nodes are also removed. The number of glands removed will depend on the size and type of the cancer, what the surgeon can see and feel at the time of the operation and the results of any scans performed before the operation.
Many patients are able to go home 1-3 days after their operation.
Because of where the thyroid gland lies in the neck it is possible for the following to occur after a thyroid operation:
- Hoarse Voice
This can occur when the nerve that supplies the vocal cords is ‘bruised’ or damaged during the operation. The voice changes in this case are usually temporary.
Sometimes the nerve has to be cut in order to get the thyroid gland and the cancer out, this is rare however and your surgeon will talk to you about any expected risks before the operation.
- Low calcium levels
This can happen when the parathyroid glands (there are 4 of them) that sit close to the thyroid gland are removed or get ‘bruised’ during the operation. These glands control the calcium levels in the blood. If they are not working normally the calcium level will be low. The calcium level will be checked by a blood test after your operation and if the levels are low you will be given extra calcium either as a tablet or through a drip. Your surgeon will talk to you about this in more detail.
When the thyroid gland is removed, thyroid hormone medication is needed to replace the thyroid hormones that the body can no longer make. Thyroxine tablets need to be taken once a day and are usually best taken first thing in the morning.
It might take a little while to get the right dose for each patient. But once the dose is sorted you should feel your normal self as the tablets are replacing the hormones that your thyroid gland would have produced. The dose will be monitored by finding out how you feel and by checking blood tests (TFTs).
(If you are going to need radioactive iodine treatment you may be put on Tri-iodothyronine tablets to start with. This is given as a tablet 3 times a day). You will need to carry on with thyroid hormone medication for the rest of your life.
If you use any over the counter health supplements including multivitamins it is worth checking with your doctor whether the time of day you take these these tablets needs to be changed. Some tablets can reduce the amount of thyroxine you can absorb from you stomach into the bloodstream so leaving at least a 2 hour gap can be helpful.
RAI Part 1
This is only used for Papillary and Follicular thyroid cancers.
Like ordinary iodine in the diet, radioactive iodine is taken up by any remaining normal thyroid cells and potentially by thyroid cancer cells as well. The radioactive form of iodine is used to destroy any remaining thyroid cells.
Before this treatment can be given, the patient needs to be prepared so that the treatment stands the best chance of working
Preparing for RAI
Step 1 – Low Iodine Diet
This is recommended in order to get as much of the radioactive iodine to the treatment areas of the body and to stop iodine in the diet from interfering with the treatment.
There is quite a variation in the amount of time that different hospitals and doctors suggest for the low iodine diet.
You are likely to be asked to cut down the amount of iodine in your diet for between 1 and 2 weeks before your treatment. You will be able to eat normally again once the treatment has been finished.
The details of the diet will be given by your own hospital team but the main things that contain iodine that you will need to cut down or avoid are fish and dairy produce. You may find examples of low iodine diets in booklets and on internet sites that are not designed for the UK population’s diet so it is best to avoid these as they are unlikely to be suitable.
Step 2 – Producing A High Level of Thyroid Stimulating Hormone (TSH)
There are 2 ways of getting this hormone level high enough in the blood to allow the radioactive iodine to do what it needs to do.
- The first option is to stop thyroid hormone medication and allow the body to make a larger amount of TSH than usual. Many people struggle with this and can develop symptoms including tiredness, loss of appetite, weight gain, dry skin, greasy hair, constipation, mood changes and feeling cold.
- The second option is to give the TSH in an artificial way by injections (recombinant human TSH, rhTSH, ‘Thyrogen’™). The injections are given on the 2 days before the radioactive iodine and are given by injection into the muscle in the buttock. This allows the patient to continue on their thyroid hormones throughout the preparation and treatment process.
Side effects from rhTSH are uncommon and generally mild. Some people feel sick, have a headache or feel weak with aching muscles ( like having flu) after their injections. This is best managed with rest, plenty of fluids and paracetamol. A few people have experienced a rash.
rhTSH may not be available everywhere and it isn’t suitable for all patients.
RAI Part 2
If you are advised to have radioactive iodine therapy, this will need to be as an inpatient in a special cubicle known as an isotope or isolation room.
This room is specially adapted because of the high dose of radiation involved in treatment. Unlike a normal hospital ward you will not be allowed to have visitors in the room. Adult visitors (provided they are not pregnant) can visit but must stay in a designated area outside the room.
You can talk to each other either through a protective window or possibly by using a phone link. You cannot have children to visit.
The treatment dose of radioactive iodine is usually given as a capsule to swallow. The capsule is a similar size to a paracetamol capsule.
Many patients do not experience any side effects with radioactive iodine. However the following side effects can occur:
- dry mouth
- tender or swollen saliva glands
- taste changes
- sore throat
- altered sensations around your thyroidectomy scar
- swelling in the thyroid area if a significant amount of thyroid tissue is still present
- feeling sick (although this is uncommon)
You will be asked if you are pregnant before the radioactive iodine capsule is given to you. If there is any doubt then a pregnancy test will be done as the treatment cannot go ahead if you are pregnant.
After the radioactive iodine dose has been given to you, you will need to avoid becoming pregnant for 6 months or avoid fathering a child for 4 months.
Following Radioactive Iodine Treatment
The treatment will make you radioactive for a period of time afterwards and therefore you will need to stay in the isolation room whilst the levels of radiation are very high. The levels of radiation will be monitored whilst you are in the room and once the readings have fallen enough (often after 3-4 days) you will be allowed to go home.
You will have a full body scan using a gamma camera (see www.goingfora.com/radiology) after the treatment and this is done to see where the radioiodine has gone in the body.
If you were not already on thyroxine before your treatment this needs to be started and you are likely to be given a prescription to go home with.
You will still be radioactive when you go home therefore you will still need to be careful and follow some guidelines (radiation protection measures) in order to reduce the risks to those people around you.
Here are some examples of what to expect when you go home:
- sleep alone
- try to keep more than 6 feet away from other people wherever possible
- avoid prolonged close contact with adults and particularly pregnant women and children
- avoid using public transport and going to the cinema/theatre, i.e, places where you may be seated next to the same person for prolonged periods
- flush the toilet twice
- avoid becoming pregnant for 6 months or fathering a child for 4 months
The length of time that you will need to follow the guidance varies between patients but your hospital will give you precise instructions and the date on which you can mix with adults normally and another date for when you can mix with children and pregnant or potentially women.
If you are planning to travel by ferry or plane shortly after your treatment then it may be advisable to carry a letter stating that you have recently received radioactive treatment. This is to avoid any confusion that may be caused by sensitive radiation recording devices at airports and ferry terminals.
Other Radioactive Treatments
Some patients with medullary thyroid cancer may be suitable for radioactive treatment using different types of radioactive chemical. An example is mIBG (metaiodobenzylguanidine) treatment.
Although mIBG also uses radioactive iodine it is very different to the treatment explained above. This treatment is given in the isolation room but needs to be given through a drip into the bloodstream rather than as a capsule to swallow.
It is important to monitor blood pressure readings during this type of treatment and to give anti-sickness medicine before the treatment starts.
It is likely that the stay in the isolation room will be between 5 and 7 days and again a full body scan using a gamma camera will be done afterwards to see where the chemicals have gone in the body. There is no need to stop thyroid hormones before this type of treatment. However some other medications may need to be changed or stopped before mIBG treatment and your hospital team will advise you on this issue.
Radiotherapy (X-ray Treatment)
This type of treatment is not commonly used in thyroid cancer. It is more often used to treat Anaplastic and Medullary thyroid cancers but can have a role to play in any type.
The reasons why this type of treatment might be offered are:
- radioactive iodine treatment is not suitable or is not working
- to treat thyroid cancer cells that could not be removed by surgery
- if an operation cannot be done to remove the thyroid gland and thyroid cancer
- to treat thyroid cancer that comes back after treatment
Radiotherapy involves using powerful x ray beams to try and kill cancer cells whilst allowing the normal cells around the same area to survive.
The treatment is given in a radiotherapy department and the machines are called linear accelerators or Linacs.
Treatment is usually given over a period of several weeks on a Monday to Friday basis (no treatment at the weekends usually). You may be in the treatment room for a total of about 20 minutes each day.
It is important to keep the position of your head and neck as still as possible during treatment so a special see through plastic mask is usually made that fits snugly around the shape of your face and neck. There are lots of different types of mask but an example of one of these masks can be seen at http://www.cancerhelp.org.uk/help/default.asp?page=3598
You only wear this whilst you are on the treatment bed. You are treated lying on your back.
You do not feel anything whilst the x ray beam is switched on but you can usually hear the machine working.
The treatment is likely to cause some side effects. The commonest ones are:
- painful swallowing
- dry mouth
- dry, red, painful or blistered skin in the region of the treatment
- altered sense of taste
- (feeling sick/nausea and hair loss are not likely to occur)
The side effects will vary depending on exactly what part of the body needs treating and your doctor will explain in detail the likely effects that you might experience and whether they are likely to be temporary or longer lasting.
For further details go to: www.goingfora.com/oncology/radiotherapy_room.html
Chemotherapy (drug treatment)
This is not commonly used in thyroid cancer and therefore will not be discussed here. For information on specific chemotherapy drugs, please click this link.
Radioactive Iodine Treatment
If you have had radioactive iodine treatment for papillary or follicular thyroid cancer, you will need a follow up assessment between 9-12 months after treatment to check your response and to decide if any further radioactive iodine treatment is needed.
The follow up process does vary slightly but will involve one or more of the following:
- Thyroglobulin blood test
- Neck ultrasound scan
- Radioactive iodine full body scan. This is used less commonly. (Again you will need to have a high TSH level and will either need to stop thyroid medication temporarily or have rhTSH injections. You will need to follow similar restrictions – including not getting pregnant – to when you had the treatment in the isolation room [even though this is done as an outpatient] as you will be made radioactive again.)
Unlike other more common cancers, patients with a diagnosis of thyroid cancer usually remain on follow up in the clinic life long. After the initial period of treatment and follow up clinic visits, the subsequent follow up is often only needed on a once yearly basis.
Your follow up clinic visits will usually involve seeing the doctor, having your neck area examined; blood tests (e.g. thyroid function test (TFT), calcium, thyroglobulin (Tg. To monitor papillary and follicular thyroid cancer), calcitonin and CEA (to monitor medullary thyroid cancer) and sometimes scans.
This is needed for a number of reasons including monitoring thyroid hormone levels and to check for signs of cancer having returned. For some types of thyroid cancer it is possible for cancer to show itself again many many years later and that is why it is sometimes necessary to carry on with follow up for so long.
Many patients, very understandably, ask about their prognosis. It is extremely difficult to predict an individual’s risk of the cancer either coming back after treatment or of it shortening someone’s life.
The temptation is for patients and their relatives to ask for a timescale or likelihood of surviving the disease. The trouble is that the information that doctors have does not accurately predict what will happen for an individual patient.
The data we have on survival and the success of treatments is gained from looking at groups of patients and you cannot accurately use this to say with any certainty what will happen for one particular person. Even if someone is thought to have a type of thyroid cancer where the chances of surviving and living their life as if it never happened is thought to be excellent it cannot be guaranteed. Likewise someone with a type of thyroid cancer that is expected to behave in a more aggressive fashion may do very well and hence better than expected.
The following website link provides figures for thyroid cancer survival for patients in the UK during 2005 but please remember it cannot predict what will happen to you:
Information on current clinical trials can be found at the following websites:
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