Tests for carcinoid tumour of the bowel and stomach

Some carcinoids make hormones and these can cause the symptoms of carcinoid syndrome. Blood tests can help to show if your carcinoid is making hormones. Your tests will include one to measure the amount of serotonin in the blood and one to measure the amount of a protein called chromogranin A (CgA). Chromogranin A levels in blood need to be checked at specialist laboratories and so the result takes at least a week.

Carcinoid tumours - especially carcinoids of the small bowel - sometimes release high amounts of serotonin. The body breaks down serotonin to a substance called 5HIAA. We get rid of 5HIAA in our urine, so a raised amount in the urine can be a sign of carcinoid. Your doctors will ask you to collect all your urine over 24 hours to measure the amount of 5HIAA. While you are collecting urine for this test, you should avoid eating foods which are rich in serotonin, such as bananas, avocados, walnuts, pineapple and kiwi fruit.

Barium can coat the inside of organs and help them show up clearly on X-ray scans. You can have it as a drink or as an enema, depending on the part of the digestive system the doctors are checking. You have it as a drink for a barium meal or barium swallow. A barium swallow looks at the food pipe (oesophagus) and a barium meal looks at the stomach and small bowel. The radiographer takes a series of X-rays as the barium passes down through your throat and into your stomach. There is more information about barium swallow and barium meal in our section about cancer tests.

To have a barium enema, you need to have an empty bowel. So your doctor will give you a laxative to take a day before the test. You may also have an enema on the morning of the test. You should not eat any food before this test, but need to drink plenty of fluids. The doctor will run a mixture of white liquid barium and water into your bowel through the tube and take a series of X-ray pictures of your bowel. The barium helps any lumps or swelling show up in the pictures. You can find more information about barium enema in the cancer tests section.

A CT scanner takes X-rays from different angles to form a detailed image of the inside of your body. The doctor uses the scan to see whether there is a carcinoid tumour, how big it is and whether it has spread anywhere else.

A few hours before the scan, you drink a liquid that helps to make the scan clearer. You can’t eat or drink for 4 hours beforehand (called 'nil by mouth').

You will have more of the special liquid while in the X-ray department. Or if your scan is of the lower part of your bowel, your doctor may put the liquid into your back passage (rectum) just before the scan. There is further information about CT scans in our cancer tests section.

An MRI scanner uses magnetism rather than X-rays to build up a picture. MRI scans are especially good at showing up soft tissue in the body. For this scan you need to change into a special gown and remove jewellery and other metal objects. During the scan you need to lie very still. You may find the test very noisy. You will have earplugs or headphones to help block out the noise. There is detailed information about MRI scans in the cancer tests section.

A PET scanner uses a mildly radioactive liquid injected into a vein. The liquid is a type of sugar (glucose) that gets taken up by the tumour cells so the scan may show if there are any tumours. There is more information about PET scans in our section about cancer tests.

An endoscopy looks at the inside of your digestive system. You may have medicines (sedatives) to make you drowsy for the test. You lie down on a bed and your doctor sprays the back of your throat with a local anaesthetic. Then the doctor passes a flexible tube down your throat to the area they want to see in the food pipe (oesophagus) or stomach. Your doctor may take a biopsy at the same time. There is information about endoscopy in the cancer tests section.

An endoscopic ultrasound (EUS) is the same as having an endoscopy. But the endoscopy tube takes pictures using ultrasound. By doing the ultrasound at the same time, your doctor can see the inside of your food pipe (oesophagus) and stomach. They can also see ultrasound pictures of the outer layers of the gut and the area around it. They may also take a biopsy during the EUS.

A colonoscopy is a type of endoscopy that looks at the large bowel (colon), and back passage (rectum).

Before this test your bowel must be empty and you may need to take laxatives. You may also need to have an enema. Your doctor or nurse will give you full instructions about this. You may have medicines to make you drowsy (sedated) and then lie on your side on a bed. Your doctor passes a flexible tube into your back passage (rectum) and up into your bowel. They will take pictures of your bowel, and take biopsies of any abnormal areas. You can find further information about colonoscopy in the diagnosing bowel cancer section.

If your tests show an abnormality your doctor may want you to have a biopsy. A biopsy is a small sample of tissue taken from the affected area. Your doctor may do this when you have a colonoscopy, endoscopy or endoscopic ultrasound (EUS). If it isn’t possible to take a biopsy during one of these tests, your doctor may take the tissue sample during a small operation. You will need to have a general anaesthetic for this.

Octreotide is a substance that carcinoid cells may take up (absorb). Doctors can attach a radioactive substance to the octreotide which then shows up on a scan. Your doctors will give you the substance as an injection and you have a scan using a special type of scanner. Doctors call this test an octreoscan (or somatostatin receptor scintography). You usually have three scans over 3 days, starting on the day of the injection.

The scan may show an area where the radioactivity has collected. This shows where the carcinoid tumour is in the body and if it has spread anywhere else.

An MIBG scan is another type of radioactive scan. Some carcinoid tumours take up a chemical called MIBG (Meta-lodo-Benzyl-Guanidine). By attaching a small amount of a radioactive substance to the MIBG, your doctor may be able to see the tumour on a scan. Your doctor gives you the MIBG as an injection into a vein in your arm. You then lie on the scanner and your doctor takes pictures of the area. The pictures show where the radioactivity has collected. For some carcinoid tumours this is a good way of showing where the carcinoid is and if it has spread to other parts of the body.

These scans do not make you radioactive afterwards and it is safe to be with your family or friends.

If you have carcinoid syndrome or a carcinoid in your small bowel you have a higher risk of heart disease. You will have an echocardiogram at diagnosis and continue to have regular check ups. If you have any changes in your heart, you will see a doctor who specialises in heart problems. You may need to take tablets to help. Some people may need to have surgery to the heart valves.