In the early stages of having a carcinoid tumour, you may not have any symptoms.

You may also not have symptoms if the tumour is just in your digestive system, as any hormones it produces will be broken down by your liver.

If symptoms do develop, they tend to be fairly general and can be easily mistaken for signs of other illnesses.

Symptoms may result from both the tumour itself and from any hormones it releases into the bloodstream.

Symptoms will depend on where in the body the tumour develops.

• A bowel carcinoid tumour may cause tummy pain, a blocked bowel, diarrhoea, constipation, feeling or being sick, and bleeding from the bottom.
• A lung carcinoid tumour may cause a cough, coughing up blood, wheezing, breathlessness, chest pain and tiredness.
• A stomach carcinoid tumour may cause pain, weight loss, tiredness and weakness.

Some tumours may not cause any symptoms and are discovered by chance. For example, an appendix carcinoid tumour may only be found when the appendix is being removed for another reason.

Typical symptoms of carcinoid syndrome include:

• Diarrhoea, tummy pain and loss of appetite
• Flushing of the skin, particularly the face
• Fast heart rate
• Breathlessness and wheezing

These symptoms may come on unexpectedly, as the hormones can be produced by the tumour at any time.

Some people may also develop carcinoid heart disease, where the heart valves thicken and stop working properly.

There is also a risk of developing a rare but serious reaction called a carcinoid crisis, which involves severe flushing, breathlessness and a drop in blood pressure.

It is not known exactly why carcinoid tumours develop, but it is thought that most occur by chance.

Your chances of developing a carcinoid tumour may be increased if you have:

• A rare family syndrome called multiple endocrine neoplasia type 1, also known as MEN1
• Parents or siblings with a carcinoid tumour
• Parents with squamous cell skin cancer, non-Hodgkin lymphoma, or cancer of the brain, breast, liver, womb, bladder or kidney
• Conditions called neurofibromatosis or tuberous sclerosis

A carcinoid tumour may be found incidentally, for example, as a surgeon is removing an appendix. In this case, the tumour will often be caught early and removed along with the appendix, causing no further problems.

Otherwise, people usually see their GP after they have developed symptoms. A carcinoid tumour may be diagnosed after carrying out a series of scans and tests. This may include measuring the amount of serotonin in your urine and having an endoscopy.

If the tumour is caught early, it may be possible to completely remove it and cure the cancer altogether.

Otherwise, surgeons will remove as much of the tumour as possible. This is called debulking.

If the tumour cannot be removed, but it is not growing or causing symptoms, you may not need treatment straight away. It may be carefully monitored.

If it is causing symptoms, you may be offered one of the following treatments:

• Injections of medicines called somatostatin analogues, such as octreotide and lanreotide, which can slow down the growth of the tumour
• Radiotherapy to kill some of the cancer cells
• A procedure to block the blood supply to the tumour, known as hepatic artery embolisation
• A procedure that uses a heated probe to kill cancer cells, called radiofrequency ablation
• Chemotherapy to shrink the tumour and control your symptoms

Symptoms of carcinoid syndrome can be treated with injections of octreotide and lanreotide. You may also be given medication to widen your airways and anti-diarrhoea medication.

There are things you can do yourself to manage some of the symptoms of carcinoid syndrome.

Generally, you should avoid triggers of flushing, such as:

• Alcohol
• Large meals
• Spicy foods
• Foods containing tyramine, such as aged cheese and salted or pickled meats
• Stress

Some medications, such as selective serotonin reuptake inhibitor antidepressants, also known as SSRIs, may make symptoms worse by further increasing your levels of serotonin.

Never stop taking medication without seeking medical advice.

If you have diarrhoea, it is important to keep drinking little and often to avoid dehydration.

If the whole tumour can be removed, this may cure the cancer and symptoms altogether.

Even if surgeons cannot remove the entire tumour, it usually grows slowly and can be controlled with medication.

Overall, people with carcinoid tumours have a good life expectancy compared to many other cancers, with around 70 to 80% surviving at least 5 years from diagnosis. Many people remain relatively well and lead active lives, with only occasional symptoms.

As the tumour grows or spreads, it will produce more and more hormones, and it may eventually be difficult to completely control symptoms with medication. You may need further surgery or other treatments.

Unfortunately, life expectancy is not as good for cancer that has spread to other parts of your body, because it will not usually be possible to remove all of it. However, treatment can still control your symptoms and slow down the spread of cancer.

If you have carcinoid syndrome, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service, also known as NCARDRS.

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.