Transarterial radioembolization explained

Prof Charles Sanyika explains transarterial radioembolization, a minimally invasive and highly targeted treatment for liver tumours.

Transarterial radioembolization (TARE), also known as selective internal radiation therapy (SIRT), is a form of targeted internal radiation therapy used to treat liver cancers. 

It involves delivering tiny radioactive particles directly into the blood vessels that supply cancerous tumours in the liver. This enables a high dose of radiation to be delivered to the tumour while minimising exposure to healthy liver tissue.

The radioactive element most commonly used is yttrium-90 (Y-90), a pure beta-emitting isotope that delivers high-energy radiation over a very short distance, making it ideal for localised treatment within the liver. Holmium-166 can also be used but this is currently not available in SA.

NB: TARE doesn’t make you radioactive to others. The radiation remains inside the liver and poses no risk to family or caregivers.

TARE is mainly used in patients with:

• Primary liver cancers, especially hepatocellular carcinoma (HCC).
• Secondary (metastatic) liver tumours, commonly from colorectal cancer.
• Tumours that are unresectable (can’t be removed surgically) or aren’t responding well to chemotherapy.
• Patients being considered for liver transplantation (as bridging or downstaging therapy).
• Selected patients where there is portal vein invasion by the liver cancer and other loco regional therapies may not be suitable.

TARE may not be suitable in some patients due to:

• Severely impaired liver function.
• Extensive tumour involvement of the liver (>50%).
• Poor general performance status where the patient is in palliative treatment.
• Significant lung shunting (where a large amount of treatment could reach the lungs) of unavoidable passage of the radioactive particles into the stomach or intestines.
• Abnormal liver blood flow patterns that prevent safe delivery of therapy.
• Previous significant radiation injury to the liver.

How is TARE selected for patients?

A decision to offer TARE is made by a multi-disciplinary team (MDT), including medical oncologists, hepatologists, liver or transplant surgeons, interventional radiologists (IR), and nuclear medicine specialists. This team carefully evaluates liver function, overall health, tumour characteristics, and previous treatments before recommending TARE.

How are the liver blood vessels accessed?

TARE is performed by an IR, using imaging to guide a catheter to the blood vessels supplying the tumour. 

The procedure is typically done under local anaesthesia with sedation, although some cases may require general anaesthesia depending on individual needs and institutional protocols.

The IR inserts a catheter into an artery through one of the following:

• Left wrist – radial artery access
• Groin – femoral artery access

Using live X-ray guidance (fluoroscopy), the catheter is threaded into the liver’s blood vessels that supply the tumour.

TARE involves two hospital visits

Visit 1: Planning and lung shunt study

• A pre-treatment simulation using safe radioactive particles, technetium-99m.
• Special imaging scans are done to check whether any particles might travel to the lungs or gastrointestinal organs.This info is used to calculate the dose of radiation to be administered, ensuring safe and precise delivery of radiation.

Visit 2: Radioembolization treatment

• In SA, treatment usually takes place about two weeks after the planning study, as the radioactive microspheres are specially imported per patient.
• You will need to arrive fasting and the procedure lasts around 60–90 minutes. Generally, you will be admitted overnight for observation.

What to expect after treatment?

• You may experience mild fatigue, low energy, or flu-like symptoms.
• Pain is rare, and when present, typically mild.
• Pressure is applied over the access site (for several hours) using special devices or standard pressure bandages to allow it to seal and prevent bleeding.
• There may be bruising or a small scar at the access site.
• No skin stitches are necessary.
• Patients are generally admitted overnight for observation, though the procedure may also be done as a day case.
• Light activities can usually resume within a few days.
• You should return to work within a week, depending on how you feel.

Potential side effects

Although rare, possible risks include:

• Radiation-induced liver injury — especially if liver function is already impaired.
• Non-target embolization — where microspheres unintentionally reach the stomach or gallbladder. 
• Lung radiation exposure — if significant shunting occurs.

These risks are significantly reduced by thorough planning, especially the lung shunt study performed beforehand.

Follow-up imaging

Follow-up is co-ordinated by the MDT team and usually involves CT, MRI, or PET-CT scans to assess tumour response; blood tests to monitor liver function; and evaluation of whether further treatment is needed.

Decisions about resuming or modifying other cancer therapies are also made at this stage.

Can TARE be repeated?

Yes, in selected situations, such as new tumours arise in a different region of the liver; there is residual disease after the initial treatment; or the patient is undergoing downstaging before liver transplant.

TARE is available at specialised centres in Johannesburg, Pretoria, Durban, and Cape Town. Your referring doctor or oncologist can help you connect with a centre.

8 Anslow Crescent, Anslow Office Park, Bryanston 2021, South Africa

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