Radiotherapy for carcinoid

Radiotherapy uses high energy waves to kill cancer cells. The radiotherapy targets the cancer cells. It may also damage nearby normal cells but these can recover. Doctors sometimes recommend radiotherapy for carcinoid that has spread and is causing symptoms. You can have radiotherapy for carcinoid either as targeted (radio labelled) radiotherapy or from an external radiotherapy machine.

All cells have receptors that cause changes in the cell when they are triggered. For example, they may tell it to

• Make more cells
• Release substances
• Stop releasing substances

Special scans can show whether carcinoid tumours have particular receptors that doctors can use target radiotherapy. Doctors can attach radioactivity to the substances that trigger the receptors. These substances are very specific to the carcinoid cells, so the radioactivity is targeted at destroying only carcinoid cells.

There are different types of targeted radiotherapy

• 131 I-MIBG (Meta-ldo-Benzyl-Guanidine)
• Octreotide -90-Y-octreotide

131 I-MIBG (Meta-ldo-Benzyl-Guanidine)

MIBG is one substance taken up by carcinoid cells. Doctors attach radioactive iodine to the MIBG. The carcinoid cells absorb the MIBG and so pick up the radioactivity as well. We know from research that this treatment controls symptoms in 4 out of 5 people (80%). You need to be in hospital for a few days while you have this treatment. You have a room on your own because the treatment makes you slightly radioactive for a few days. This means your visitors, nurses and doctors will only be able to spend a short time with you. This is a precaution and is to protect them from being exposed to too much radiation from all the patients they look after.

Your sweat and urine are radioactive while you are in hospital. The hospital may have rules about changing your sheets daily and may ask you to flush the toilet more than once after you use it. Usually the levels of radiation fall within a few days and you are able to go home. After treatment your levels of red and white blood cells and platelets may be lowered. This can make you feel tired and increase your risk of infection for a while. Most people recover quickly from this treatment.

Octreotide 90 Y

Octreotide 90 Y is a newer type of targeted radiotherapy. Octreotide is similar to a naturally occurring hormone, called somatostatin. Doctors call octreotide a somatostatin analogue. By attaching radioactivity to the octreotide we can kill the carcinoid cells.

You can also have octreotide without the radioactivity as a treatment for carcinoid syndrome and as a treatment before surgery. You can find more information in our section about other somatostatin analogues.

Research has shown that octreotide 90 Y treatment can reduce the size of the tumour in around 3 out of 10 people (30%) treated. It can reduce the symptoms in 6 out of 10 people (60%) treated.

The main side effects associated with octreotide are

• A bloated feeling
• Feeling sick
• Diarrhoea
• A drop in blood cell counts (very rarely)
• Kidney damage  - this is very rare

We need further research to find out about the longer term side effects of octreotide 90Y. Some doctors have reported damage to bone marrow in some patients, which can lead to a condition called myelodysplastic syndrome. This means your bone marrow has trouble making enough new healthy blood cells.

It is very rare for carcinoid to spread to the bones or brain but if it does you usually have external radiotherapy (from the outside of your body). It is especially helpful in controlling pain. You may have just one treatment or treatment for a few days. You may feel tired afterwards but the side effects are usually mild. Radiotherapy to the brain causes hair loss in the treatment area but this grows back after a few months.