Radioembolisation is a minimally invasive interventional oncology procedure used to treat selected cancers in the liver. It combines catheter-based embolisation with internal radiation therapy. Tiny microspheres containing a radioactive substance, most commonly yttrium-90 (Y-90), are delivered through the hepatic artery into the blood vessels supplying the tumour.
The microspheres become lodged mainly within the tumour’s small blood vessels and emit radiation over a short distance. This delivers a concentrated radiation dose within the tumour while limiting exposure to much of the surrounding healthy liver tissue. Unlike conventional embolisation, the main treatment effect comes from the radiation rather than from completely blocking the tumour’s blood supply.
Radioembolisation is also known as selective internal radiation therapy (SIRT) or transarterial radioembolisation (TARE). It may be used alone or combined with surgery, ablation, systemic therapy or external radiation therapy as part of a multidisciplinary treatment plan.
- Hepatocellular carcinoma, the most common form of primary liver cancer
- Selected intrahepatic cholangiocarcinomas
- Liver metastases from colorectal cancer
- Neuroendocrine tumours that have spread to the liver
- Selected liver metastases from breast cancer, melanoma or other cancers
- Liver-dominant cancer, where most of the active disease is within the liver
- Tumours that cannot be treated safely with surgery or thermal ablation
- Patients who are not suitable for surgery because of other medical conditions or insufficient future liver reserve
- Selected patients requiring treatment to reduce or control a tumour before surgery or liver transplantation
- Patients being considered for downstaging to another treatment
- Selected patients requiring treatment of a liver segment or lobe while encouraging growth of the untreated liver before surgery
- Patients with liver tumours that have progressed despite other treatments
How Radioembolisation Therapy Is Performed
Before Treatment
The treating team reviews the diagnosis, biopsy findings, imaging, previous treatments and medical history.
CT, MRI, PET-CT or other imaging is used to assess the tumours, blood-vessel anatomy and extent of disease within and outside the liver.
Blood tests are performed to assess blood counts, blood clotting, kidney function and liver function.
Blood-thinning medicines and certain other medications may need to be temporarily adjusted under medical guidance.
The patient is asked about allergies, particularly previous reactions to contrast material.
Pregnancy and breastfeeding must be discussed because radioactive material is used.
The patient is usually instructed to avoid eating or drinking for a specified period before the procedure.
A planning angiogram, also called a mapping angiogram, is usually performed before treatment.
During mapping, a catheter is guided into the hepatic arteries to identify the vessels supplying the tumour and any branches leading to the stomach, bowel or other non-target areas.
Selected blood vessels may be closed with small coils when necessary to reduce the risk of microspheres reaching healthy organs.
A tracer is injected to simulate the distribution of the microspheres.
Nuclear medicine imaging is then used to assess blood flow to the liver, detect unintended flow outside the liver and measure the amount that could reach the lungs.
The results are used to determine whether treatment can be performed safely and to calculate an individualised radiation dose.
Mapping and treatment are often performed on separate days, although same-day treatment may be possible in selected settings.
During Treatment
The patient lies on an angiography table while their heart rate, blood pressure and oxygen levels are monitored.
Local anesthesia and sedation are commonly used, although general anesthesia may be required in selected cases.
A small puncture is made in an artery, usually at the groin or wrist.
A thin catheter is guided through the blood vessels towards the hepatic artery using X-ray imaging.
Contrast material is injected to confirm the arterial anatomy and catheter position.
A smaller catheter may be advanced closer to the tumour to deliver treatment selectively to a segment, lobe or larger area of the liver.
The prescribed radioactive microspheres are slowly delivered into the arteries supplying the tumour.
The microspheres become lodged within small tumour blood vessels and begin releasing radiation.
One or more liver regions may be treated depending on the distribution of disease and the planned dose.
The catheter is removed after treatment, and pressure or a closure device is used at the puncture site.
The procedure generally takes approximately one to two hours, although the duration varies with the blood-vessel anatomy and extent of treatment.
Imaging may be performed after the procedure to confirm the distribution of the radioactive microspheres.
After Treatment
The patient is monitored in a recovery area while the effects of sedation wear off.
If the catheter was inserted through the groin, the patient may need to keep the leg straight for several hours.
Pain relief, fluids, anti-nausea medicines and other supportive treatment are provided as needed.
Many patients can return home on the same day, while some may require overnight observation.
Tiredness, reduced appetite, nausea, mild abdominal discomfort or a low-grade fever may occur following treatment.
The patient receives instructions about medicines, hydration, activity and care of the catheter-entry site.
Strenuous activity and heavy lifting may need to be avoided for a short period.
Temporary radiation-safety precautions may be advised, including limiting prolonged close contact with children or pregnant people for a specified period.
Blood tests are arranged to monitor liver function, kidney function and blood counts.
Follow-up CT, MRI, PET-CT or other imaging is used to assess treatment response.
Tumour changes may develop gradually over several weeks or months, so response is not usually assessed immediately.
Additional radioembolisation, systemic therapy, ablation or another treatment may be recommended depending on the response and remaining disease.
Potential Benefits of Radioembolisation Therapy
- Minimally invasive treatment through a small arterial puncture
- Delivery of radiation directly into the blood vessels supplying liver tumours
- A concentrated radiation dose within the tumour
- Limited radiation exposure to much of the surrounding healthy liver tissue through selective catheter placement
- Treatment of multiple tumours supplied by the targeted artery
- Treatment of selected tumours that cannot be removed surgically or safely treated with ablation
- An option for selected patients whose cancer has not responded to other treatments
- The potential to reduce or control tumours before surgery or liver transplantation
- The possibility of downstaging selected tumours to make another treatment feasible
- Treatment of a liver segment or lobe while encouraging enlargement of the untreated liver in selected patients being prepared for surgery
- A shorter recovery period than major surgery in many cases
- A short hospital stay, with same-day discharge possible for some patients
- A lower incidence of post-embolisation syndrome than is generally seen with TACE or bland embolisation
- The ability to combine treatment with surgery, ablation, systemic therapy or other cancer treatments
Side Effects of Radioembolisation Therapy
- Tiredness or weakness
- Reduced appetite
- Nausea or vomiting
- Mild fever or flu-like symptoms
- Abdominal pain or discomfort
- Bruising, bleeding or swelling at the catheter-entry site
- Temporary changes in liver or kidney function
- Allergic reaction to contrast material
- Damage to the artery, including spasm, clotting or dissection
- Radioactive microspheres reaching tissue outside the intended treatment area
- Inflammation or ulceration of the stomach, duodenum, gallbladder or pancreas
- Bile-duct injury or liver abscess
- Radiation-related injury to healthy liver tissue
- Temporary or permanent liver failure, particularly in patients with limited liver reserve
- Radiation-related lung injury if an excessive number of microspheres reaches the lungs
- Reduced blood counts, particularly when a large liver volume is treated
- Incomplete tumour control or continued cancer progression
- Rare blood clots, infection or serious reactions related to sedation or anesthesia
