Carcinoid syndrome

What is carcinoid syndrome?

Some ​neuroendocrine tumours (NETs) make large amounts of ​hormones​ and proteins. The most common substance they make is ​serotonin. 

They sometimes release serotonin and the other proteins into the bloodstream. This can cause a collection of symptoms called carcinoid syndrome.

Carcinoid syndrome is most common in people with a small bowel NET which has spread to the liver. It can also happen in people with lung and pancreatic NETs. But this is less common.

Find out more about small bowel NETs

Symptoms of carcinoid syndrome

The main symptoms of carcinoid syndrome are: 

Flushing of the skin

The skin of your face, neck and chest might look red (flushed). It may also feel warm and itchy.

85 out of every 100 people (85%) with carcinoid syndrome have this symptom.

Diarrhoea

Diarrhoea means you have changes to:

• the consistency of your poo (stool) - for example it is more watery than usual

• how often you are going - for example over 24 hours you might have 2 or more loose bowel movements than usual

• how much you are passing (the volume) when you have your bowels open

Diarrhoea can be severe. Some people with carcinoid syndrome have diarrhoea more than 30 times a day. 

80 out of every 100 people (80%) with carcinoid syndrome have diarrhoea.

Other symptoms

Other symptoms of carcinoid syndrome include:

• tummy (abdominal) pain

• red spidery marks on your skin caused by small broken blood vessels - this is called telangiectasia

• a whistling sound when breathing - this is called wheezing

• fast heartbeat and palpitations

• a build up of fluid in your legs and ankles

Complications of carcinoid syndrome

Rarely, people with carcinoid syndrome may develop other complications. These include:

• carcinoid heart disease

• carcinoid crisis

Your doctor regularly checks for these.

Carcinoid heart disease

Carcinoid heart disease happens when there is a build up of plaque or scar tissue in the heart valves and the heart muscle. Over time, the valves become thicker and this can affect how the heart works.

Doctors don’t fully understand why this happens. They think it’s because some NETs make large amounts of hormones and proteins. And these can build up around the heart. 

Carcinoid heart disease happens in up to 50 out of every 100 people with carcinoid syndrome (up to 50%). 

Symptoms of carcinoid heart disease are usually vague. Most people don’t have any symptoms until it is severe. Symptoms include:

• feeling breathless

• tiredness (fatigue)

• a build up of fluid in your body causing swelling

• weight loss

Carcinoid crisis

Carcinoid crisis is a more serious version of carcinoid syndrome. It happens when NETs make large amounts of hormones and proteins. 

A carcinoid crisis can happen for no reason. In some people, an anaesthetic or treatment such as surgery or chemotherapy can set it off. 

Symptoms of carcinoid crisis are severe and might include:

• sudden, severe changes to your blood pressure - this might cause you to feel dizzy and pass out

• palpitations

• difficulties with breathing and a whistling sound when breathing - this is called wheezing

• sudden severe redness of the skin - this is called flushing

• very severe (profuse) diarrhoea

Tests to diagnose carcinoid syndrome

You usually have tests to diagnose carcinoid syndrome. This helps your doctor plan your treatment. The tests you might have include:

Blood tests

These check for substances raised by NETs including:

• ​chromogranin A​

• N-terminal pro-brain natriuretic peptide (NT-proBNP) - this is a protein that helps doctors assess how well your heart is working

You might also have tests to measure different mineral and vitamin levels in your blood.

Urine tests

Your body breaks down the hormone serotonin into a substance called 5-HIAA. Your doctor can test for this in your wee (urine) or you might have this as a blood test. You usually collect all your urine over 24 hours. You might need to repeat this test.

CT scan

A ​CT scan​ can show up whether the NET has spread to the liver.

Radioactive scans

These include:

• octreotide scans (or ​octreoscans) 

• gallium dotatate ​PET scans​

• MIBG scans

You have an injection of a low dose radioactive substance, which is taken up by some NET cells. The cells then show up on the scan.

Heart tests

If your doctor suspects carcinoid heart disease, you usually have a heart test. This is called an ​echocardiogram.  If you have any changes to the way your heart works, you see a doctor who specialises in heart problems. 

Read about tests for neuroendocrine cancer

Treatment for carcinoid syndrome

The main aim of treatment is to reduce your symptoms. This means reducing the amount of hormones and proteins the NET is making. This won’t get rid of the NET but can control your symptoms and help you feel better. 

Treatment also aims to:

• prevent carcinoid heart disease, or stop it from causing further damage

• make sure you are getting the right nutrition from your diet and supplements

Treatment options for carcinoid syndrome

The main treatment for carcinoid syndrome are ​somatostatin analogues​. These are medicines such as octreotide or lanreotide. 

Somatostatin inhibitors can help lower the hormones which cause carcinoid syndrome. This helps to control symptoms such as diarrhoea and skin flushing. They might also shrink the tumour. 

If this treatment doesn't work, your doctor might suggest:

• surgery to remove the cancer from your liver, or to remove as much as possible - this is called debulking surgery

• trans arterial embolisation (TAE) which blocks the blood supply to a NET in the liver 

• a type of ​internal radiotherapy​ called selective internal radiation therapy (SIRT)

• a type of ​radioactive​ medicine called peptide receptor radionuclide therapy (PRRT)

• a type of ​targeted cancer drug​ called everolimus

Read about these treatments

Treatment options for carcinoid heart disease

You have the same treatments as for carcinoid syndrome to lower your hormone levels. You can read about these treatments further up the page.

To treat carcinoid heart disease your doctor might suggest:

• medicines for treating heart conditions

• changes to your diet - for example being careful about fluid and salt intake

• surgery to replace affected heart valves with an artificial valve (prosthesis) 

You have regular tests to monitor your heart function. These include blood tests and echocardiograms.

Treatment options for carcinoid crisis

Carcinoid crisis is a medical emergency. Contact your doctor and go to your local A&E if you think you have this.

To prevent carcinoid crisis, you might have a somatostatin analogue called octreotide. You can have it as an injection, or as a continuous drip into your vein. 

Doctors monitor you closely for carcinoid crisis. If you develop it, you may have treatment with:

• somatostatin analogues

• steroids

• fluids into your vein (intravenous)

• some types of drug which can control your blood pressure

Managing diet and nutrition problems

It is important that you are getting all the minerals and vitamins that you need. This can be a problem for people with carcinoid syndrome. Your healthcare team will decide if you need any extra support with your diet. They consider many factors such as:

• any weight loss

• bowel problems such as diarrhoea

• vitamin and mineral levels in your blood tests

• whether you have had surgery to your bowel, stomach or pancreas

They will refer you to a ​dietician​ to give you advice about your diet. They might also prescribe medicines to:

• make sure you get all the nutrition you need

• try and help to control diarrhoea

Read more about diet and neuroendocrine cancer

Coping with carcinoid syndrome

It can be difficult to cope with carcinoid syndrome and its complications. You might have ongoing symptoms such as diarrhoea and flushing of the skin that are difficult to control.

As well as the treatments your doctor recommends, you can do other things to help with the symptoms. There is also practical help and support for you and your family.

Coping with flushing of the skin

You might find it helps to keep a record of your skin flushes to see if anything in particular makes them worse. For example, some people find that stress can trigger them.

Other common triggers include:

• exercise

• drinking alcohol or caffeine

• eating foods that contain a substance called tyramine such as chocolate, bananas and walnuts

• eating large meals or spicy foods

Avoiding the triggers that cause skin flushing can help to control it.

Coping with diarrhoea

You lose a lot of fluid when you have diarrhoea. It is important to replace the fluid to prevent dehydration. Drink little and often and try to drink at least 2 to 3 litres a day.

Although it is usually healthier to eat a diet high in fibre, this can make diarrhoea worse. Fatty, greasy foods can also make it worse. Some foods such as rice, pasta and dry biscuits tend to make your poo (stool) firmer so try these instead.

When you have diarrhoea for a long time, the levels of vitamins in your body can drop. Your doctor might advise you to take a vitamin supplement to prevent this from happening.

Read more about coping with diarrhoea

Ways to cope

It isn’t easy to cope with carcinoid syndrome. People often think they have an idea of what having cancer is like, but NETs are different from other cancers. You might have ongoing symptoms and treatment that other people don’t understand. You may find that you have to explain to people what it all means.

It's important to give yourself time. Adjusting to major changes in your life is never easy, and can take a while. There isn’t a right or wrong way to cope with carcinoid syndrome. You need to find the best way for you. 

You might have physical changes to your body because of your cancer or the treatment. These changes can be hard to cope with and can affect the way you feel about yourself. It can help to talk to friends and family. Or join a support group to meet people in a similar situation.

We have a discussion forum called Cancer Chat. It is a place for anyone affected by cancer. You can share experiences, stories and information with other people with cancer.

Visit Cancer Chat

You might need practical advice about benefits or financial help. There is help and support available. There are also organisations to support and provide information to people affected by neuroendocrine cancer.

We have information about living and coping with a neuroendocrine cancer