Selective internal radiation therapy (SIRT) | Cancer Research UK
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Selective internal radiation therapy (SIRT)

SIRT is a type of internal radiotherapy treatment for liver cancers that can’t be removed with surgery. You have tiny beads called microspheres put down a thin tube into the main blood vessel that supplies blood to your liver. They block the small blood vessels around the tumour. So the tumour can’t get the nutrients it needs to grow. The microspheres contain a radioactive substance that destroys the tumour cells.

Tests before SIRT

You have a CT scan and blood tests. You also have a planning angiogram to look at the blood supply to the liver and block off tiny blood vessels that lead to other areas of the body. This prevents the microspheres from causing damage to healthy tissues.

Having SIRT

You have SIRT about 1 or 2 weeks after the planning angiogram. You may have sedation to help you relax.You have an injection of local anaesthetic to numb your groin. Your doctor makes a small cut and puts a thin tube called a catheter into a blood vessel called the femoral artery.

Using X-rays, the doctor guides the catheter up the femoral artery into your liver. They then inject the microspheres through the catheter. The whole process takes about an hour.

After the treatment, you have a dressing over the small wound in your groin. You need to lie flat for a few hours. Most people need to stay in hospital overnight.

Side effects of SIRT

The common side effects are generally mild and include

  • A raised temperature
  • Chills
  • Feeling sick
  • Diarrhoea
  • Stomach ache
  • A feeling of pressure in the abdomen

These side effects usually only last a few days. Your nurse will give you medicines to help.

Tiredness is one of the most common side effects and can last up to 6 weeks.

Radiation safety

You should avoid close contact with young children and pregnant women for the first 10 days after treatment. Your doctor or nurse will give you advice before you go home. Most of the radiation has gone within 2 weeks.

Follow up

You will have regular check ups, blood tests and scans after treatment.

 

What is selective internal radiation therapy (SIRT)?

SIRT is a way of using radiotherapy to control liver cancers that can’t be removed with surgery. It is a type of internal radiotherapy. It is sometimes called radioembolisation.

You have tiny beads called microspheres put down a thin tube into the main blood vessel that supplies blood to your liver (the hepatic artery). Each bead is smaller than the width of a human hair. They get stuck in the small blood vessels around the tumour.

The microspheres contain a radioactive substance. The radiation travels a short distance to treat the cancer. The microspheres are also called SIR-spheres or TheraSpheres.

 

How SIRT works

The microspheres block the small blood vessels around the liver tumour and reduce the blood supply. So the tumour can’t get the nutrients it needs to grow. The radiation from the microspheres destroys the tumour cells.

The microspheres give off radiation to an area only a few millimetres on average around where they are trapped. This means they cause very little damage to the surrounding healthy tissue.

 

Who can have SIRT

SIRT is available on the NHS in England, Scotland and Wales through the Commissioning through Evaluation (CtE) programme. The aim of this programme is to increase access to services and treatments which are not routinely funded by the NHS. They say that SIRT can be used within the NHS for

  • Bowel cancer that has spread to the liver
  • Bile duct cancer (intrahepatic cholangiocarcinoma)

At the moment, SIRT is only for people who can’t have surgery and the cancer has not responded to chemotherapy.

You must be well enough to have SIRT and your liver must be working well. If your specialist thinks you are suitable for SIRT they can refer you to a specialist centre.

If you have primary liver cancer (hepatocellular carcinoma) that can’t be removed with surgery, you may have SIRT as part of a clinical trial.

If you can't take part in a trial, or you have another type of cancer that has spread only to the liver, your specialist may apply for funding to see if you can have the treatment within the NHS. If you have private medical insurance, the insurance company may fund SIRT.

 

Tests before SIRT

Before you have SIRT, you have tests to assess your liver and plan your treatment.

CT scan

A CT scan shows where the tumours are in your liver and their size. So your doctor can check that SIRT is a suitable treatment for you. If you have recently had a CT scan for something else, you may not need another one.

 Read about having a CT scan

Blood Tests

You will have blood tests to check

  • The number of different blood cells (a full blood count)
  • How well your kidneys and liver are working
  • There are no problems with your blood clotting

 Read about blood tests

A planning angiogram

An angiogram looks at the blood supply to the liver, which varies from person to person. The doctor (called an interventional radiologist) blocks off tiny blood vessels that lead to other areas of the body such as the stomach or lungs. This stops the SIRT microspheres from travelling to other areas of the body and causing damage to healthy tissue.

First you may have some sedation to help you relax. Then you have an injection of local anaesthetic to numb your groin. The doctor makes a small cut and puts a thin tube called a catheter into a blood vessel called the femoral artery.

Using X-rays, the doctor guides the catheter up the femoral artery into your liver. They then inject a dye to show up the blood vessels. They can see the images on a screen. The dye might make you feel warm for a few seconds and you may feel as though you need to pass urine.

The doctor can see if there are blood vessels that lead to other areas of the body and can block them. This doesn’t harm the areas that these small blood vessels go to. The procedure may take 60 to 90 minutes but can take longer.

Lung shunting scan

After the angiogram, the doctor injects a radioactive tracer into the catheter. The tracer is similar in size to the SIRT microspheres. You then have a scan that picks up the radioactive tracer. This is called a lung shunting scan or scintigraphy. This takes about an hour. It shows where the microspheres will go when you have the treatment. This helps your doctor to work out if it is safe to go ahead with the treatment.

You need to lie flat for several hours after these tests. This helps the wound in your groin to heal. You can usually go home at the end of the day or the following morning.

 

How you have SIRT

You have SIRT about 1 or 2 weeks after the planning angiogram. You might have it on its own or with chemotherapy.

To have SIRT you have another angiogram. When the catheter is in the right place, the doctor slowly injects the microspheres into your liver. The whole process takes about an hour.

After the treatment you have a dressing over the small wound. You need to lie flat for a few hours to allow the wound to heal properly. Most people need to stay in hospital overnight. Your nurse will give you painkillers and anti sickness medicines if you need them.

You can watch a video of a patient having SIRT on the My SIRT Story website.

 

Side effects of SIRT

Generally the common side effects of SIRT are mild. They include

  • A raised temperature
  • Chills
  • Feeling sick
  • Diarrhoea
  • Stomach ache
  • A feeling of pressure in the abdomen

These side effects usually only last a few days. Your nurse will give you medicines to help. If you develop a high temperature (above 38°C) contact your doctor or the hospital as you may have an infection.

Tiredness

Tiredness is a common side effect and can last up to 6 weeks. This is normally mild, so you can still do normal everyday activities. Severe tiredness is quite rare. Talk to your specialist nurse if you are worried.

Irritation to the gut

Rarely, a small number of the microspheres can travel to the digestive system (gut). This can cause

  • Pain in your abdomen
  • Feeling or being sick
  • Bleeding
  • A stomach ulcer
  • Inflammation of the pancreas (pancreatitis)

To prevent irritation to the stomach, your doctor will give you anti ulcer medicines for around 4 weeks after treatment.

Lung damage

If the radioactive beads go to the lungs they can cause inflammation. This is very rare. It may cause a cough and shortness of breath. You may have steroids to help.

Inflammation of the liver

This can affect how well your liver works, and may happen weeks after the treatment. You will have regular blood tests (liver function tests) to check this.

Your liver function might get better by itself after a few weeks. Or you may need steroids. Damage to the liver can be life threatening, but this is extremely rare.

Inflammation of the gallbladder

This is called cholecystitis. Symptoms include

  • Pain
  • Fever
  • Feeling or being sick

It may get better without treatment, but in rare cases you may need surgery to remove the gallbladder.

 

Radiation safety after SIRT treatment

The range of radiation from the microspheres is very small. But as a precaution, you should avoid close contact with young children and pregnant women for the first 10 days after treatment. Close contact means being within arm's length of the person who has had treatment. Your doctor might also advise you to not share a bed for the first 4 days.

Your doctor or nurse will give you advice about the precautions before you go home. Most of the radiation has gone within 2 weeks. The microspheres stay in the liver permanently, but are harmless.

 

Follow up

Your specialist will follow you up closely after treatment. How they do this varies slightly between hospitals.

You might have blood tests every week at first to check how well your liver is working. You may have a CT scan 6 and 12 weeks after treatment. Your doctor and specialist nurse will talk to you about how often you will have check ups and scans.  

 

Research into SIRT

Doctors have looked at SIRT for cancers that have started in the liver (primary liver cancer), and cancers that have spread to the liver from another area of the body, such as bowel cancer and neuroendocrine tumours.

As SIRT is a relatively new treatment, doctors are still looking into

  • How well this treatment works
  • How it affects quality of life
  • If it helps people to live longer

Doctors have to record and monitor the results of all SIRT treatments on the national SIRT register. Where possible, you may have treatment as part of a clinical trial.

Clinical trials

Several trials are in progress.

FOXFIRE

A phase 3 trial called FOXFIRE is testing SIRT in combination with chemotherapy as a first treatment for bowel cancer that has spread to the liver. This trial is no longer recruiting patients and the results should be available later this year.

SIRFLOX

Recently, the international SIRFLOX trial compared SIRT and FOLFOX chemotherapy (with or without a biological therapy drug called bevacizumab) with chemotherapy alone. The triaI used these treatments as a first treatment for advanced bowel cancer.

The cancer had either spread only to the liver or mainly to the liver and a small number of other areas, such as the lymph nodes or lungs. Around 530 people took part.

The researchers found that the combination of treatments was better at temporarily stopping the cancer from growing in the liver than chemotherapy alone. The average length of time it took for the cancer to start growing again was around 12 months with just chemotherapy, and around 20 months for those having both SIRT and chemotherapy.

The researchers are still following up the people who took part in the trial and so it is too early to know if SIRT helps people to live longer overall.

SARAH

A large study in France, called the SARAH study, has recently finished recruiting patients. The people taking part have primary liver cancer (hepatocellular carcinoma) that can’t be removed with surgery.

The researchers are comparing SIRT with the biological therapy drug, sorafenib. Results for this trial are expected later this year.

STOP-HCC

An international trial called STOP-HCC is looking at SIRT before starting sorafenib for primary liver cancer.

SORAMIC

Part of the SORAMIC trial is comparing sorafenib alone with sorafenib and SIRT for primary liver cancer that cannot be removed with surgery. This is part of an international trial where doctors are also looking at sorafenib after a treatment called radiofrequency ablation.

You can search for trials in the UK on our clinical trials database.

 

Related information

Find out about

Internal radiotherapy

Secondary cancer in the liver

Primary liver cancer

Bowel cancer

Bile duct cancer

My SIRT Story – information for patients about SIRT

For general information and support

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Updated: 4 May 2016