What is medullary thyroid cancer?

Medullary thyroid cancer (MTC) is a rare type of thyroid cancer. Less than 5% of thyroid cancers are MTC.

It is often slow-growing. It 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.

We also have information about other types of thyroid cancer, including:

Related pages

What is cancer?

Symptoms of medullary thyroid cancer

The most common symptom of medullary thyroid cancer is a swelling or lump in the neck, which may be painful.

Other symptoms may include:

difficulty swallowing – caused by the tumour pressing on the gullet (oesophagus)
difficulty breathing – caused by the tumour pressing on the windpipe (trachea)
a hoarse voice for no obvious reason, that does not go away after a few weeks
a feeling of pressure or discomfort in the neck.
a flushed face
having softer poo (stool) or diarrhoea often.

The last 2 symptoms can be caused by a tumour making too much of the hormone calcitonin.

All these symptoms can be caused by conditions other than cancer. But it is important to get them checked by your GP.

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Do I have cancer?

Causes of medullary thyroid cancer

Doctors do not know the exact causes of medullary thyroid cancer (MTC). But there are risk factors that can increase your chance of developing it.

For about 3 in 4 people (75%) who develop MTC, the cause is unknown. This is called sporadic medullary thyroid cancer.

Multiple endocrine neoplasia (MEN2)

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

There are 2 types of MEN2:

MEN2A – this is the most common type
MEN2B – this is sometimes called MEN3.

Most people with MEN2 will develop MTC unless they have an operation to remove the thyroid gland at an early age. This is to prevent cancer developing.

If you are diagnosed with MTC, you may have a blood test to look for genetic changes. If the test shows changes to the RET gene, your doctor will refer you to a specialist genetics service. The specialist will give you more information about the gene changes. They will also discuss whether any members of your family may also need to be tested.

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Family history, genes and cancer risk

Diagnosis of medullary thyroid cancer

Medullary thyroid cancer may be found:

if you have symptoms
during genetic screening tests, if you have a close family member with MTC.

If you have symptoms, you will usually begin by meeting with your GP. They will examine the lump or swelling in your neck and ask about any other symptoms you might have. The GP will usually do some blood tests to check how well your thyroid is working.

If they think it could be cancer, you should have a hospital appointment. This is usually within 2 weeks.

At the hospital, the specialist doctor will ask you about your general health, any previous medical problems and your family history. They will also examine you. You may 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 thyroid cancer can sometimes spread to the lymph nodes. The scan only takes around 10 to 15 minutes and is painless.
Fine needle aspiration (FNA)

A doctor gently passes a small needle into the lump or swelling in your neck. Sometimes the doctor uses an ultrasound scan 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 for any abnormal cells. This is a type of biopsy.

If an FNA does not collect enough cells, or the results are not clear whether the cells are cancerous or not, it may need to be done again.

Waiting for test results can be a difficult time. We have more information that can help.

Further tests

Your specialist may arrange further tests to find out more about the cancer or to check whether it has spread:

These tests may include the following:

Blood tests

These check for the levels of calcitonin in your blood. You may also have a blood test to check the levels of a protein called carcinoembryonic antigen (CEA) in the blood. CEA is a tumour marker. It can help your doctor monitor how well treatment is working.
Blood or urine test

Some people also have a blood test or a 24-hour urine collection. This is to check for a rare, usually non-cancerous tumour called a phaeochromocytoma. It affects the adrenal glands which are on top of the kidneys and is linked to MEN2.
CT scan

A CT scan takes a series of x-rays. These build up a three-dimensional (3D) picture of the inside of the body.
MRI scan

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

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Staging and grading of medullary thyroid cancer

The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging.

A doctor decides the grade of the cancer by how the cancer cells look under the microscope. This gives an idea of how quickly the cancer might grow or spread.

Knowing the stage and grade helps your doctors plan the best treatment for you.

We have more information about staging of medullary thyroid cancer.

Treatment for medullary thyroid cancer

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your treatment will depend on:

the stage of the cancer
the results of tests on the thyroid cancer cells
your general health
your preferences.

Your doctor or cancer specialist or nurse will explain the different treatments and their side effects. They will also talk to you about things to consider when making treatment decisions. You will need this information before you give your permission (consent) to have any treatment.

Your cancer team may also give you advice about preparing for your treatment. This is sometimes called prehabilitation. It helps to improve your fitness and diet and to get you ready mentally before treatment.

Treatments may include:

Surgery

Surgery is the main treatment for MTC. A surgeon usually removes the whole thyroid gland. This is called a total thyroidectomy. They may also take out some lymph nodes. If your thyroid gland has been removed, you will need to take thyroid hormone tablets called levothyroxine every day for the rest of your life.
External beam radiotherapy

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

It is sometimes given after surgery to try to reduce the risk of the cancer coming back. You may also have radiotherapy to improve symptoms or if the cancer has spread to other parts of the body.
Targeted therapy
Targeted therapy drugs target something in or around the cancer cell that is helping it grow and survive are used to treat MTC if:

you cannot have surgery to improve symptoms

the cancer has come back

the cancer has spread.

Cabozantanib (Cometriq®), selpercatinib (Retsevmo®) and vandetanib (Caprelsa®) are targeted therapy drugs that may be used to treat MTC. These drugs cannot cure medullary thyroid cancer, but they can slow its growth and help with symptoms.
Radionuclide therapy

Radionuclide therapy is a type of internal radiotherapy. It is not often used to treat medullary thyroid cancer. It uses a radioactive substance, which is attached to a type of chemical, to destroy the cancer cells. The treatment is given as a drip into a vein
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.

You may have some treatments as part of a clinical trial.

Treating advanced medullary thyroid cancer

Even if it has spread, MTC may grow slowly. It might not cause any symptoms for many years.

Your doctor might recommend regular blood tests and scans. If they find changes, for example a rise in calcitonin, your doctors may talk to you about further treatment.

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After medullary thyroid cancer treatment

Follow-up after treatment for medullary thyroid cancer

You will have regular check-ups during and after your treatment. You may have blood tests and scans to monitor your condition and general health.

After surgery you will have blood tests to check the levels of calcitonin and a protein called CEA. These blood tests are used to look for any signs of the MTC coming back after surgery.

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

Follow-up appointments are a good time to talk to your cancer doctor or specialist nurse about any concerns you have. Tell them as soon as possible if you have any problems or notice new symptoms between appointments.

We have more information about follow-up care after treatment.

Wellbeing and recovery

It can take time to recover after thyroid cancer treatment. Some days you may feel better than others.

A healthy lifestyle can help speed up your recovery. Even small lifestyle changes may improve your wellbeing and long term health.

Even if you already have a healthy lifestyle, you may choose to make some positive changes after treatment. We have more information on leading a healthy lifestyle after treatment.

More information and advice

We know cancer can affect you physically, emotionally and financially. We have information and advice about different ways cancer might impact you, such as help with:

Support after medullary thyroid cancer

People often have many different feelings when they finish medullary thyroid cancer treatment. You may feel relieved that treatment has ended, but worried about what will happen in the future.

It is important to know where to get support or information if you need it. People often need support even if it has been some time since they finished cancer treatment. But sometimes it is difficult to know who to ask for help.

To find support:

ask your GP or someone from your cancer team for advice about support in your area
find cancer support services near you
call the Macmillan Support Line on 0808 808 00 00
chat to our cancer information specialists online
visit our Online Community thyroid cancer forum to talk to people who have been affected by thyroid cancer, share your experience, and ask questions.

The HOPE programme is a free 6 week self-management course designed to help you develop techniques and strategies when living with or after cancer.

Topics include goal setting, fatigue management, and wellbeing. You can sign up for the online HOPE programme. Or to find out more about face to face programmes in your area, email ServiceOpsSupport@macmillan.org.uk

Other organisations who offer information and support

There are also other organisations that can give you information and support. These include:

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References

Below is a sample of the sources used in our medullary thyroid cancer information. If you would like more information about the sources we use, please contact us at

informationproductionteam@macmillan.org.uk

Datta R. British Medical Journal Best Practice Guidelines, Thyroid cancer. 2023. British Medical Journal. Available from: www.bestpractice.bmj.com/topics/en-gb/263

Kaliszewski K, Ludwig M, et al. Update on the Diagnosis and Management of Medullary Thyroid Cancer: What Has Changed in Recent Years? 2022. Cancers, Vol. 14; P.3643. Available from: www.doi.org/10.3390/cancers14153643

Cancer Information Development team

Author

Date reviewed

Reviewed: 01 October 2024

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Next review: 01 October 2027

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