Selective internal radiation therapy (SIRT)
Selective internal radiation therapy (SIRT) is a type of internal radiotherapy used to treat secondary and sometimes primary liver tumours that cannot be removed with surgery.
It may be used to treat:
- cancer that has spread to the liver from the large bowel or other places in the body
- cancer that started in the liver (primary liver cancer).
SIRT uses radioactive beads. It is also called radioembolisation. It is not the same as chemoembolisation (also called TACE or CT-ACE), which uses chemotherapy and sometimes plastic beads.
SIRT is not widely available and is not always funded by the NHS. You may have it as part of a research trial. If your cancer team think it is suitable for you, you may have to travel to a specialist hospital to have it.
Tiny radioactive beads are injected into the bloodstream. They stick permanently in the small blood vessels in and around the liver tumour. The beads give off radiation, which damages the cancer cells. They also block the blood vessels to the tumour. This stops the blood supply to the tumour so it does not get the oxygen and nutrients it needs.
The radioactivity of each bead only affects tissue that is very nearby. It also affects the cancer cells more than nearby healthy cells. This means the tumour is treated but areas of healthy liver are not damaged. The beads lose their radioactivity quickly and are most effective in the first 2 days. They stay in the body permanently, but this does not cause any problems.
Your doctor will arrange tests before you have treatment. These help your team to decide whether you will benefit from SIRT. The tests also help plan your treatment.
A sample of your blood is taken to check:
- the levels of different types of cells in your blood (a full blood count)
- how well your kidneys and liver are working
- how quickly your blood clots.
If you have bowel cancer, your blood may also be tested for a protein called carcinoembryonic antigen (CEA). Some people with bowel cancer have higher levels of this protein. So, doctors may check this regularly to see how well a treatment for bowel cancer is working.
An angiogram is a test that uses x-rays to look at blood vessels. A planning (or pre-SIRT) angiogram shows the blood supply to your liver. This helps your doctor see where the SIRT beads would go when they are injected.
You have this test in the x-ray (radiology) department of the hospital. You are asked not to eat or drink anything for several hours before. Your team also gives you instructions about any medication you usually take. This includes drugs that thin your blood, such as aspirin or warfarin.
You are given a local anaesthetic injection to numb the skin on one side of your groin or wrist. The doctor then makes a small cut in the skin. They gently put a thin, flexible tube called a catheter into a blood vessel in your groin or wrist. The catheter is guided up the blood vessel to the liver.
The doctor injects dye into the catheter and takes x-rays to see where the dye goes. This shows where the SIRT beads would travel in the bloodstream. The doctor uses tools through the catheter. They close off any small blood vessels that would take the beads away from the tumour to other parts of the body. This does not harm the areas that are closed off.
The doctor then injects a liquid called a radioactive tracer. After the angiogram, you have a scan that finds this liquid. It shows where the SIRT beads will go to in your liver. It also checks that none would escape from the liver to other parts of the body, such as the bowel or lungs. This helps your doctor know if it is safe for you to have the treatment. If the scan finds tracer outside the liver, you may need another planning angiogram before you have SIRT.
After the angiogram, you have to lie flat for a few hours if the cut was made in your groin. If the cut was made in your wrist, you can sit up straight away. Try to drink at least 1½ (3 pints) of water in the 24 hours after your test. This helps clear the dye from your body.
You should not drive for 24 hours after the test. Avoid heavy lifting and vigorous exercise for 3 days.
You usually have the treatment 1 to 2 weeks after the planning angiogram.
You are awake for the treatment, but may be given medication to help you relax. This may make you feel sleepy. You may also be given anti-sickness medicine. You have another angiogram, and this time SIRT beads are injected into the catheter. This usually takes less than an hour. If you have any pain during the treatment, let your doctor or nurse know. They can give you painkillers.
You may need to stay in hospital overnight, or for a few days, when you have the treatment. Before you go home, your doctor or nurse will explain any medication you need to take. Some medications are to reduce the chance of serious side effects. So it is important to let your team know if you cannot take them. They will also explain any possible side effects and who to contact if you need advice.
Your treatment is planned to give you the amount of radiation needed to treat the cancer safely and effectively. But your team are also careful to protect other people around you from radiation. Safety measures may be slightly different in different hospitals. Your team will explain what to expect.
Almost all the radiation from each SIRT bead is absorbed by the area of the body closest to it. But your body fluids will be slightly radioactive for a time. It is safe for you to be around most other people. As a precaution, you may have to avoid close contact with children or pregnant women for a time.
Your team will explain this and any other safety measures you need to know about or follow at home. This may include instructions about:
- using the toilet and cleaning up any spilled body fluids safely
- not sharing a bed or having sex for a few days
- not breastfeeding or using expressed breast milk for a few weeks.
Your team will also give you information to carry with details of your treatment.
We explain the most common side effects of this treatment here. You may get some of the side effects we mention, but you are unlikely to get all of them. These side effects are usually short-term and get better with time.
You may also have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.
Rarely, SIRT can cause side effects that start weeks after treatment. Sometimes these may be serious or need urgent treatment. Your team will explain the risk of these side effects to you.
Problems at your injection site
There may be bruising or a small lump where the angiogram catheter went into your groin or wrist. You should let your nurse or doctor know straight away if you notice any:
Feeling sick (nausea)
You may be given an anti-sickness (anti-emetic) drug to prevent nausea before you have SIRT. Tell your doctor or nurse if you feel sick after treatment. They can give you tablets to help. Nausea usually only lasts for a few days.
We have more information on nausea.
Tummy (abdominal) pain
Some people have tummy pain during SIRT. Let your doctor or nurse know about any pain you have during or after treatment. They can give you painkillers to help with this.
Rarely, some beads may escape from the liver to the stomach or bowel. This can irritate the lining of the stomach or bowel and cause tummy pain or indigestion. You may be given medicine to take regularly which will help. Tell your doctor or nurse straight away about any pain.
High temperature (fever)
This treatment can cause a high temperature for a few days. Fever is a common side effect of SIRT, but it can also be a sign of infection.
When you are home, contact the hospital straight away on the contact number you have been given if:
- your temperature goes over 37.5°C (99.5°F)
- you suddenly feel unwell, even with a normal temperature
- you have symptoms of an infection – this can include feeling shaky, a sore throat, a cough, diarrhoea or needing to pass urine a lot.
Tiredness can last from a few days up to several weeks after treatment. It is important to get enough rest and eat a balanced diet to help your body recover. Keeping a treatment diary can help you record your energy levels and plan activities for when you are feeling stronger.
We have more information on coping with tiredness.