Medullary thyroid cancer (MTC)

Medullary thyroid cancer (MTC) is a rare type of thyroid cancer. It is often slow-growing. The most common symptom of MTC is a mass or lump in the neck.

If your GP thinks you may have cancer, they will refer you to a specialist. At the hospital, the doctor will ask you about your general health and any previous medical problems.  They will take a detailed family history. You will also have a physical examination and some tests.

If the tests show you have cancer, your specialist will do more tests to find out the size and position of the cancer and whether it has spread to other parts of the body. This helps them understand the stage of the cancer and how best to treat it.

Treatment for MTC may include:

  • surgery
  • radiotherapy
  • targeted therapies

It’s common to be overwhelmed by different feelings when you’re told you have cancer. There is no right or wrong way to cope, but help is there if you need it.

What is medullary thyroid cancer (MTC)?

Medullary thyroid cancer (MTC) is a rare type of thyroid cancer. It is often slow-growing.

MTC starts in cells in the thyroid gland called parafollicular cells or C cells. These cells normally make a hormone called calcitonin, which controls the level of calcium in the blood.

About 3 to 8% (3 to 8 out of 100) of adults diagnosed with thyroid cancer have MTC.

We also have information about other types of thyroid cancer including follicular, papillary and anaplastic thyroid cancer and thyroid lymphoma.


The thyroid gland

The thyroid is a small gland in the front of your neck just below your voicebox (larynx). It is made up of two parts called lobes, which are connected by a thin bridge of thyroid tissue called the isthmus.

The thyroid gland
The thyroid gland

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The thyroid gland is part of your endocrine system, which makes hormones to keep your body systems in balance. Your thyroid gland produces hormones, which control your metabolism and maintain the balance of calcium in your blood. These are:

  • thyroxine (T4)
  • triiodothyronine (T3)
  • calcitonin.


Causes and risk factors

About 25% of people (1 in 4) who develop MTC have a rare inherited condition called multiple endocrine neoplasia 2A (also called MEN2) multiple endocrine neoplasia 2B (also called MEN3) or familial medullary thyroid cancer (FMTC). These are rare conditions. MEN2A and MEN2B can also cause growths (tumours) in other endocrine glands.

Almost everyone with the MEN2A or MEN2B gene change will develop MTC. Because of this, children and young adults with the MEN2A or MEN2B gene usually have an operation to remove the thyroid gland. This is to prevent cancer developing.

If you are diagnosed with MTC, you will be advised about a blood test to look for genetic changes.  And you are likely to be referred to a specialist genetics service.


Signs and symptoms

Possible symptoms of MTC include:

  • a painless lump in the neck
  • difficulty swallowing – this can be caused by a thyroid tumour pressing on the gullet (oesophagus)
  • changes in breathing – this can be caused by a thyroid tumour pressing on the windpipe (trachea)
  • a hoarse voice, for no obvious reason, that doesn’t go away after a few weeks
  • a cough, for no obvious reason, that doesn’t get better after a few weeks
  • a feeling of pressure or discomfort in the neck.

Less common symptoms include:

  • flushing
  • loose stools or diarrhoea.

These can be caused by the tumour making calcitonin.


How MTC is diagnosed

You will usually see your GP who will examine you and arrange for tests. If your GP thinks you may have cancer, they will refer you to a hospital for specialist advice and treatment.

If you have a family history of MEN2A or MEN2B, your GP will also refer you to a genetics specialist for advice and treatment.

At the hospital, the doctor will ask you about your general health and any previous medical problems. The doctor will also take a detailed family history. You will have a physical examination. You will have some of the following tests:

Ultrasound scan of the neck

This scan uses sound waves to build up a picture of the thyroid gland and lymph nodes in your neck. Lymph nodes drain fluid from the tissues and help the body fight infections. There are groups of lymph nodes on either side of the neck. If cancer spreads from the thyroid, one of the first places it can spread to is nearby lymph nodes. An ultrasound only takes a few minutes and is painless.

Fine needle aspiration cytology (FNAC)

A doctor will gently pass a small needle into the swelling in your neck. This could be either your thyroid gland or a lymph node. You may have a local anaesthetic to numb the area. Sometimes the doctor will use an ultrasound scanner to help guide the needle to the right area. They will then take a small sample of cells and examine it under a microscope to check whether there are cancer cells present.

Further tests

If the tests show you have cancer, your specialist may want to do some further tests.

These may include any of the following:

Blood tests

These will check for the levels of calcitonin and calcium in your blood.

You may also have a blood test to check the levels of a protein called CEA in the blood.

24-hour urine sample

Some people who have MEN2A or MEN2B may have non-cancerous growths, called phaeochromocytomas, on the adrenal glands. This test checks if the adrenal glands are affected. It is done even if there is no family history of MEN 2A or MEN2B.

You save all the urine you pass in a 24-hour period so that it can be tested for various substances. You will be given a bottle and instructions about collecting your urine.

CT scan (computerised tomography scan)

A CT scan takes a series of x-rays. These build up a three-dimensional picture of the inside of the body.

MRI scan (magnetic resonance imaging scan)

MRI uses magnetism instead of x-rays to build up a detailed picture of areas of your body.


Staging of MTC

The stage of a cancer describes its size and if it has spread from where it started. The stage of your thyroid cancer helps your doctors decide which treatment is best for you.

There are different ways of staging cancers. The most common staging system for MTC is the TNM system.

T describes the size of the tumour and whether it has spread into nearby tissues around the thyroid gland. There are four levels. They range from T1, where the tumour is less than 2cm and hasn’t grown outside the thyroid gland, to T4, where the tumour is of any size and has spread to nearby tissues.

N describes whether the cancer has spread to the lymph nodes close to the thyroid gland. There are two levels:

  • N0 – the lymph nodes are not affected
  • N1 – the cancer has spread to lymph nodes close to the thyroid gland or in the neck or chest area.

M describes whether the cancer has spread to other parts of the body, such as the lungs or the bones (metastatic or secondary cancer).

Doctors often use the TNM information and group it into numbered stages:

Stage 1 – the tumour is no bigger than 2cm. It has not grown or spread outside the thyroid gland.

Stage 2 – the tumour is between 2 and 4cm. It has not grown or spread outside the thyroid gland. Or

the tumour is larger than 4cm or has grown slightly outside the thyroid. It has not spread to the lymph nodes or other parts of the body.

Stage 3 – the tumour is any size or has grown slightly outside the thyroid. It has spread to nearby lymph nodes. It has not spread to other parts of the body.

Stage 4 – stage 4 is divided into 3 groups, A to C:

  • Stage 4A – the tumour has grown outside the thyroid gland and into surrounding tissues. It may or may not have spread to nearby lymph nodes. It has not spread to other parts of the body. Or
  • the tumour is any size. It may have spread outside the thyroid gland and into surrounding tissue. It has spread to lymph nodes in the outside of the neck, behind the throat or the upper chest. It has not spread to other parts of the body.
  • Stage 4B – the tumour is any size. It has spread to other parts of the neck. It may or may not have spread to nearby lymph nodes. It has not spread to other parts of the body.
  • Stage 4C – the cancer has spread to other parts of the body such as the lungs or bones.


Treating MTC

The treatment you have will depend on a number of factors including the stage of the cancer and your general health. Because MTC is a rare type of thyroid cancer, you will be referred to a specialist centre for your treatment and care.

Surgery to remove the thyroid gland

Surgery is the main treatment for MTC. A surgeon will usually remove the whole thyroid gland (total thyroidectomy). They will usually also take out the lymph nodes in the front of your neck. You may also have the lymph nodes in the side of your neck removed. It may be possible to have this operation using keyhole surgery.

Before your operation

You may be seen at a pre-assessment clinic before your operation. You will have some tests to check your general health. These may include blood tests, a chest x-ray and a recording of your heart.

Before and after surgery to remove your thyroid gland, you may also have your vocal cords checked. This is because the nerves that control your vocal cords are close to the thyroid gland.

The doctor may use a local anaesthetic spray to numb your nose and throat. They will then pass a thin, flexible tube with a small camera at the end through your nose to look at how your vocal cords move.

After your operation

You may have a drip (intravenous infusion) going into your arm to replace your body’s fluids. You should be able to start drinking an hour or so after your operation. You may find it painful to swallow at first but this should improve over the next two or three days.

You may also have one or two tubes (drains) to drain fluid from your wound. These are usually removed within 24 to 48 hours.

You will have your blood tested for calcium levels. If the calcium level is low, you will be given calcium either as a tablet or through a drip in your arm.

You will probably have some pain or discomfort after your operation, and your doctor will prescribe painkillers for you. Let your doctor or nurse know if you do have pain. Your neck might feel stiff after surgery and your nurse, surgeon or physiotherapist will show you some neck exercises to help with this.

Most people are ready to go home about one to three days after their operation.

Your specialist team will give you further information about your operation and what to expect.

Follow-up

Once your thyroid gland has been removed, you will need to take thyroid hormone tablets (levothyroxine) every day for the rest of your life. These replace the thyroid hormones your body needs to function at its normal rate. You will have regular blood tests to check your thyroid hormones are at the right level.

You will also have blood tests to check the levels of calcitonin, and sometimes CEA. These blood tests are used to look for any signs of the cancer coming back after surgery or to check your progress if your cancer has already spread.

Even if it has spread, MTC usually grows very slowly and often does not cause any symptoms for many years. Your doctor might recommend follow-up appointments with blood tests and scans. If changes are found, for example a rise in calcitonin, your doctors may plan more treatment.

External beam radiotherapy

Radiotherapy uses high-energy x-rays to treat disease. It works by destroying cancer cells in the area being treated.

External beam radiotherapy may be used:

  • if there is a high risk of the cancer coming back in your neck after surgery
  • if some parts of the cancer could not be removed with surgery
  • if your cancer has spread to other parts of the body – for example, the bones.

Planning your treatment

Planning your treatment makes sure that the radiotherapy is aimed precisely at the cancer. This is so that it causes the least possible damage to the surrounding healthy tissue. If you are having radiotherapy to your neck area, you will need to have a mould or mask made before your treatment is planned. This will keep your head in the same position for each session of radiotherapy to ensure that only the area that needs treatment is treated.

Having radiotherapy

Radiotherapy is normally given as a series of short, daily outpatient treatments with a rest at the weekend. It is given in the radiotherapy department using equipment similar to a large x-ray machine. How many treatments you have will depend on the aim of your treatment. Your doctor or nurse will be able to tell how many treatments you are likely to have.

Side effects

Radiotherapy can cause general side effects such as tiredness (fatigue). Specific side effects of radiotherapy to the neck can include:

  • pain when swallowing
  • a dry mouth or throat
  • taste changes
  • dark or red sore skin
  • a hoarse voice
  • thick saliva.

Your doctor, nurse specialist or radiotherapist will discuss any possible side effects with you before you start your treatment.

We have more detailed information about radiotherapy to the head and neck area and its side effects.

Targeted therapies

Targeted therapies are drugs that target the differences between cancer cells and normal cells.

Cabozantanib (Cometriq®) and Vandetanib (Caprelsa®) can be used to treat people with MTC that:

  • cannot be operated on
  • is causing symptoms
  • has spread.

They belong to a group of drugs called tyrosine kinase inhibitors or multikinase inhibitors. They work by blocking signals in the thyroid cancer cells that make them grow and divide. Blocking the signals may cause the cells to die. These drugs do not cure the cancer, but they can slow down its growth and help with symptoms. Talk to your doctor about possible benefits and side effects of this treatment.

These drugs may only be available in some situations. Your doctor can tell you if they are appropriate for you. Some people may be given them as part of a clinical trial. If a drug is not available on the NHS, there may be different ways you are still able to have it. Your cancer doctor can give you advice. We have further information on what to do if a treatment is not available.

Your doctor will give you more information about these drugs if they are suitable for you.

Radiolabelled therapies: MIBG and PRRT therapies

This treatment uses a radioactive substance, which is attached to a particular type of chemical, to destroy the cancer.  It is most likely to be used as part of a clinical trial.

Some MTCs absorb large amounts of certain chemicals. MIBG (meta-iodobenzylguanidine) is one of these. To treat these tumours, MIBG can be attached to a radioactive substance. You are given the MIBG, and as the cancer absorbs the chemical, it also absorbs the radioactivity. This will destroy cancer cells.

You will have a scan, using a tiny amount of radioactive substance, to test whether or not the tumour absorbs large quantities of these chemicals. If it does, the treatment will be given using a higher dose of the radioactive substance.

MIBG is given as a drip into a vein (intravenous infusion). It’s given in a specialist ward. You will need to be looked after in a room by yourself for a few days. This is, so that other people are not exposed to the radioactivity. You will be radioactive for a little time after going home and will be advised on avoiding long and close contact with people. Your medical team will give you all the advice you need.

PRRT (peptide receptor radionuclide therapy) treatment is similar but the radiation restrictions are less strict and you may be in hospital for only one to two days.

After these treatments, you will need to have regular blood tests for at least a few weeks.

Your specialist will explain more about these treatments if one of them is suitable for you.

Chemotherapy

Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. It’s rarely used to treat MTC, but may be used to help with symptoms if the cancer has spread to other parts of the body.

Clinical trials

Research trials are done to try to find new and better treatments for cancer. Because MTC is rare, it is difficult to research new treatments. Ask you thyroid specialist if there are any clinical trials suitable for you.

ClinicalTrials.gov is a website that has up-to-date international clinical trials including UK trials.


Your feelings

It is common to feel overwhelmed by different feelings when you are told you have cancer. These can include anger, fear and resentment. Some people find it helpful to talk to family or friends, while others prefer to seek help from people outside their situation. Some people prefer to keep their feelings to themselves. There is no right or wrong way to manage your feelings.

Having these feelings can be difficult and sometimes people need more help to cope with them. This happens to lots of people and doesn’t mean you are not coping. If you feel anxious, panicky or sad a lot of the time, or think you may be depressed, talk to your doctor or nurse. They can refer you to a doctor or a counsellor who can help. They may also be able to prescribe medicine to help with anxiety or depression.

Our cancer support specialists can give you information about support in your area. We have a thyroid cancer information nurse who you can arrange to speak with.

Our information about the emotional effects of cancer talks about the feelings you may have in more detail, and has suggestions for coping with them.


Other useful organisations

The following organisations can also give you information and support:

  • British Thyroid Foundation
    A UK charity that supports people with thyroid disorders and their family and friends.
  • Butterfly Thyroid Cancer Trust
    This charity offers support to people affected by thyroid cancer. You can talk to others with thyroid cancer through their helpline, by email and telephone, or by arranging for a buddy to help you through the treatment process.
  • Thyroid Cancer Support Group – Wales
    A self-help group that supports patients with thyroid cancer and their families in Wales, nationally and occasionally internationally. You can reach them on 0845 009 2737, or email them.