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 helps control the level of calcium in the blood.

About 5 to 9 out of 100 (5 to 9%) of thyroid cancers are MTC.

MTC may develop in people who have a rare inherited condition called multiple endocrine neoplasia (MEN).

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

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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 of MTC

For most people, the cause of medullary cancer is unknown. This is called sporadic medullary thyroid cancer.

About 1 in 4 people (25%) who develop MTC have a rare inherited genetic condition called multiple endocrine neoplasia type 2 (MEN2). There are three types of MEN2:

  • MEN2A
  • MEN2B (also called MEN3)
  • familial medullary thyroid cancer (FMTC).

These are rare conditions. MEN2A and MEN2B can also cause growths (tumours) in other endocrine glands.

Almost everyone with MEN2 will develop MTC. Because of this, children and young adults with the MEN2 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. You are also likely to be referred to a specialist genetics service.


Signs and symptoms of MTC

The most common symptom of MTC is a lump in the neck, which may be painful.

Other symptoms may include:

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

Less common symptoms include:

  • a red face (flushing)
  • frequent loose stools or diarrhoea.

These can be caused by the tumour making too much of the hormone calcitonin.


How MTC is diagnosed

If you have symptoms, you will usually start by seeing your GP, who will examine you. If they are unsure what the problem is, or think your symptoms could be caused by cancer, they will refer you to a hospital for specialist advice and treatment. You should be seen at the hospital within two weeks.

If you have a family history of MEN2, your GP will also refer you to a specialist in genetic conditions 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. They will examine you and you will have some of the following tests.

Ultrasound scan

An ultrasound scan uses sound-waves to build up a picture of the inside of the neck and the thyroid gland. Your doctor will also check the lymph nodes in your neck to see if any of them are abnormal. This is because sometimes thyroid cancer can spread to the lymph nodes.

You will be asked to lie on your back for the scan. Once you are lying comfortably, the person doing the scan spreads a gel over your neck. Then they move a small hand-held device like a microphone around your neck area. A picture of the inside of your neck shows up on a screen. An ultrasound only takes a few minutes and is painless.

Fine needle aspiration (FNA)

A doctor gently passes a small needle into the lump or swelling in your neck. You may have a local anaesthetic to numb the area. Sometimes the doctor uses an ultrasound scanner to help guide the needle to the right area. Then they take a small sample of cells and examine it under a microscope to check whether there are any abnormal cells.

If an FNA does not collect enough cells, sometimes it is done again.


Further tests

If the tests show you that have thyroid cancer, your doctor may want to do some further tests. These are to find out the size and position of the cancer and whether it has spread to other parts of the body. This is called staging and will help you and your doctor decide on the best treatment for you.

These tests may include 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. CEA is a tumour marker. It can help your doctor monitor how well treatment is working.

24-hour urine sample

Some people who have MEN2 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 MEN2.

You collect 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)

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

PET (positron emission tomography) scan

A PET scan uses low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body.

Vocal cord check

Your doctor may need to check your vocal cords before and after surgery to remove your thyroid gland. This is because the nerves that control your vocal cords are close to the thyroid gland and they can be damaged during surgery.

The doctor may use a local anaesthetic spray to numb your nose and throat. Then they pass a thin, flexible tube with a small camera at the end (nasendoscope) through your nose to look at how your vocal cords move. This can be a little uncomfortable, but it should not be painful.

You may be asked to avoid eating or drinking for a few hours after the test, until the local anaesthetic wears off.


Staging of MTC

The stage of a cancer describes its size and whether it has spread beyond the area of the body where it started. Staging systems are often updated to help doctors plan the best treatment and give an idea of what is likely to happen. This means they are becoming more detailed and complicated.

The most common staging system is the TNM system.

TNM staging

T describes the size of the tumour and whether it has spread into nearby tissues around the thyroid gland.

N describes whether the cancer has spread to the lymph nodes close to the thyroid gland.

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

T – Tumour

Doctors put a number next to the T to describe the size and spread of the cancer. They range from T1 to T4.

T1 means the tumour is 2cm or smaller and has not grown outside the thyroid gland. T4 means the tumour is any size and has spread to nearby structures in the neck.

N – Nodes

The N may have a number written next to it, which gives information about the nodes that were examined.

N0 means the lymph nodes are not affected.

N1 means the cancer has spread to lymph nodes close to the thyroid gland or in the neck or chest area.

  • N1a means the cancer has spread to lymph nodes in the middle of the neck, close to the thyroid gland.
  • N1b means the cancer has spread to lymph nodes in the side of the neck or top of the chest.

M – Metastases

The M may have a number written next to it, which gives information about whether the cancer has spread.

M0 means the cancer has not spread within the body.

M1 means the cancer has spread to another part of the body.

Number staging

Doctors often combine the information from the TNM system into an overall number stage, from 1 to 4.

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 2cm and 4cm. The cancer has not spread to nearby lymph nodes and it is not growing outside the thyroid gland.

Or the tumour is bigger than 4cm or it has grown slightly outside the thyroid gland. The cancer has not spread to the lymph nodes or other parts of the body.

Stage 3

The tumour is any size and it may or may not have grown slightly outside the thyroid gland. The cancer has spread to nearby lymph nodes in the middle of the neck. It has not spread to other parts of the body.

Stage 4

Stage 4 is divided into three groups, from A to C:

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


Treating MTC

The treatment you have will depend on the stage of the cancer and your general health.

The main treatments used are:

Other treatments may also be used.

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 the neck. They may also remove the lymph nodes in the side of the neck.

Before your operation

You may visit 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
  • a recording of your heart (ECG).

You will see a member of the surgical team and, in some hospitals, a specialist nurse. They will talk to you about your operation. This is a good opportunity to ask questions and talk about any concerns you have. You will see the doctor who gives you your anaesthetic (the anaesthetist) either at a clinic or when you are admitted to hospital.

Before and after surgery, a doctor will check your vocal cords. 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. Then they will pass a thin, flexible tube with a small camera at the end (nasendoscope) through your nose to look at how your vocal cords move. This can be a little uncomfortable, but it should not be painful.

You may be asked to avoid eating or drinking for a few hours after the test, until the local anaesthetic wears off.

You will usually be admitted to hospital the day before or on the morning of your operation. The nurses may give you elastic stockings (TED stockings) to wear during and after the operation. These help prevent blood clots forming in your legs.

After your operation

The nurses on the ward will help you to lie in a fairly upright position, supported by pillows. This helps to reduce swelling in your neck area.

You will probably have some pain or discomfort. Your doctor will prescribe painkillers for you. Talk to your doctor or nurse about any pain you have. Your neck will feel stiff after surgery. Your nurse, surgeon or physiotherapist will show you some neck exercises to help with this.

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. 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.

There is a small risk that surgery to remove the thyroid gland will damage the parathyroid glands. These are four very small glands behind the thyroid gland. They make parathyroid hormone, which helps to control the level of calcium in your blood.

If your parathyroid glands are damaged, the level of calcium in your blood may become low (hypoparathyroidism). This can cause:

  • tingling in your hands or feet, or around your mouth
  • unusual muscle movements, such as jerking, twitching, spasms or muscle cramps.

Your blood will be 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.

Most people are ready to go home about 1 to 3 days after their operation.

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

Follow-up

If your thyroid gland has been removed, you will need to take thyroid hormone tablets (thyroxine) 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 the hormone calcitonin, and sometimes the protein carcinoembryonic antigen (CEA). These blood tests are used to look for any signs of the cancer coming back after surgery, or to check your progress if the 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 they find changes, for example a rise in calcitonin, your doctors may plan more treatment.

Radiotherapy

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

You may have external beam radiotherapy:

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

Although it is effective for some types of thyroid cancer, radioactive iodine treatment is not effective in treating MTC.

Planning your treatment

Before you start your treatment, it needs to be carefully planned. Planning makes sure that the radiotherapy is aimed precisely at the cancer, so that it causes the least possible damage to the surrounding healthy tissue.

You will need to have a mould or mask made before your treatment is planned. This is to keep your head still while you have your treatment.

Having radiotherapy

You normally have radiotherapy as a series of short, daily outpatient treatments with a rest at the weekend. You have it 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

You may develop side effects during radiotherapy. These usually disappear gradually over a few weeks or months after treatment finishes. Your radiotherapy team will let you know what to expect. Tell them about any side effects you have. There are often things that can be done to help.

Radiotherapy can cause general side effects such as tiredness (fatigue).

Specific side effects of radiotherapy to the neck can include:

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

Targeted therapies

Targeted therapies interfere with the way that cancer cells grow. They are sometimes called biological therapies.

The targeted therapy drugs cabozantanib (Cometriq®) and vandetanib (Caprelsa®) are sometimes used to treat people with MTC that:

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

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

If your cancer specialist thinks that a targeted therapy may be helpful, they will discuss this with you. But these drugs are not widely available on the NHS. Some people may have them as part of a clinical trial. If a drug is not available on the NHS, there may be different ways you can still have it. Your cancer doctor can give you advice. 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 chemicals. 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 that uses a tiny amount of radioactive substance. It tests whether the tumour absorbs a large amount of these chemicals. If it does, you will have the treatment using a higher dose of the radioactive substance.

MIBG is given as a drip into a vein (intravenous infusion). You have it 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. Your medical team will advise you on avoiding long and close contact with people. They will give you all the advice you need.

PRRT (peptide receptor radionuclide therapy) treatment is similar to MIBG. It is also given by drip into a vein and you will need to be looked after in a room on your own. But you will usually be in hospital for only 1 to 2 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 is rarely used to treat MTC. But it 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 your 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.

Follow-up

You will have regular check-ups and blood tests after your treatment has finished. Your doctor or specialist nurse will tell you how long the check-ups will continue for.

If you have any problems or notice any symptoms between check-ups, let your doctor know as soon as possible.


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.