Radioembolization is a minimally invasive procedure that combines embolization and radiotherapy to treat liver cancer. Tiny beads of glass or resin filled with the radioactive isotope yttrium Y-90 are inserted into the blood vessels that feed the tumour. This blocks the blood supply to the cancer cells and delivers a high dose of radiation to the tumour while sparing normal tissue. It may help prolong the lives of patients with inoperable tumours and improve their quality of life.
Your doctor will tell you how to prepare and instruct you on food and liquid intake before the procedure. Tell your doctor if you are likely to be pregnant or breastfeeding and discuss any recent illness, medical condition, allergy, and medications you are taking, including herbal supplements and Aspirin. You may be advised to stop taking Aspirin, non-steroidal anti-inflammatory drugs or blood thinners a few days before your procedure. Leave jewellery at home and wear loose, comfortable clothing. You may be asked to wear a gown. Ask someone to drive you home after the procedure and limit your contact with children and adults for three to seven days.
What is Radioembolization?
Radioembolization is a combination of radiation therapy and a procedure called embolization to treat liver cancer.
Embolization is a minimally invasive treatment in which blood vessels or malformations inside blood vessels are blocked, or occluded, to stop blood flow.
Radiotherapy is the use of a specific type of energy called ionizing radiation to kill cancer cells and shrink tumours. Unlike external beam radiation therapy, in which high-energy X-rays generated by a machine are directed at the tumour from outside the body, radioembolization involves placing radioactive material directly inside the body. This form of treatment is called internal radiotherapy.
In radioembolization, tiny microspheres of glass or resin are placed into the blood vessels that feed the tumour to block the blood supply to the cancer cells. Once these microspheres, which are filled with the radioactive isotope yttrium Y-90, are attached to the tumour site, they deliver a high dose of radiation to the tumour but not to normal tissues.
What are the Common Uses of the Procedure?
Radioembolization is used to treat tumours that have formed in the liver or have spread or metastasized to the liver from another part of the body. It is a palliative treatment, which means that it does not provide a cure, but instead helps to slow the growth of disease and relieve symptoms. The procedure is an option for patients who are not suitable candidates for other treatments, including surgery or a liver transplant.
How Should you Prepare?
A few days before your procedure, you will have a consultation with the interventional radiologist who will perform your procedure.
Before your procedure, your blood may be tested to determine how well your kidneys are functioning and whether your blood is clotting normally.
You will also have an angiogram, which will provide images of the blood vessels that feed the tumour, seven to ten days before your procedure.
You will need to plan your return home after the procedure, as your contact with children and adults may be limited for three to seven days.
You should tell your doctor about any medications you are taking, including herbal supplements, and if you have any allergies, especially to local or general anaesthetic medications, or to contrast agents containing iodine (sometimes called ‘dye’ or ‘X-ray dye’). Your doctor may advise you to stop taking Aspirin, non-steroidal anti-inflammatory drugs or blood thinners for a period of time before the procedure.
Also, inform your doctor of any recent illnesses or other medical conditions.
Women should always inform their physician and x-ray technologist if there is any possibility that they may be pregnant. A number of imaging studies are not performed during pregnancy to avoid exposing the foetus to radiation. If radiography is required precautions will be taken to minimise the baby's exposure to radiation.
You will be given specific instructions on how to prepare, including any changes that need to be made to your regular medication schedule.
You will be sedated during the procedure. You will be given specific instructions about your food and drink intake before the procedure and will need to ask a relative or friend to accompany you and drive you home after the procedure.
You will be given a hospital gown to wear during the procedure.
What Does the Equipment Look Like?
X-ray equipment, catheter and microspheres or tiny glass beads filled with the radioisotope yttrium-90 are used in this procedure.
Radioembolization procedures are usually performed using X-ray.
The equipment typically used for this examination consists of a radiographic table, one or two x-ray tubes, and a TV-like monitor that is located in the investigation room. Fluoroscopy, which converts the x-rays into a video image, is used to monitor and guide the progress of the procedure. The video is produced by the X-ray machine and a detector that is suspended above the table on which the patient is lying.
The catheter is a long, thin plastic tube that is significantly smaller than a ‘pencil graph’, or approximately 3.175 mm in diameter.
Millions of glass beads, equivalent to about half a teaspoon, each smaller in diameter than a human hair, deliver ionizing radiation.
Other equipment that may be used during the procedure includes an intravenous infusion system, an ultrasound machine and machines that monitor your heart rate and blood pressure.
How Does the Procedure Work?
Using X-ray imaging and contrast material to visualize the blood vessels, the interventional radiologist inserts a catheter through the skin into a blood vessel and reaches the treatment site. Radiation-filled microspheres, or glass beads, are then introduced through the catheter and guided to the blood vessels that supply the tumour with blood.
As soon as the microspheres attach to the tumour site, they deliver a high dose of radiation directly to the cancer cells. The microspheres will block the blood flow to the tumour, depriving the diseased cells of the oxygen and nutrients they need to grow.
There are two main blood vessels that supply blood to the liver. Normal liver tissue gets about 75% of its blood supply from the portal vein and about 25% from the hepatic artery and its branches. When a tumour grows in the liver, it gets almost all of its blood supply from the hepatic artery. As radioactive microspheres are delivered through the hepatic artery, they reach the tumour directly, sparing most of the healthy liver tissue.
Radiation from yttrium-90 gradually decreases over a period of 2 weeks and disappears after 30 days. The tiny microspheres remain in the liver without causing any problems.
How is the Procedure Performed?
Image-guided, minimally invasive procedures such as radioembolization are most often performed by a specially trained interventional radiologist in an interventional radiology room or, less commonly, in an operating theatre.
An initial arteriogram, as described below, is performed to visualize the superior abdominal arteries. At that time, arteries to areas of the stomach and duodenum in which beads may fall are occluded with tiny coils of wire. At the end of the procedure, a bead with a nucleated medical radioactive isotope on it is injected through the catheter to simulate the treatment. This will allow the interventional radiologist to calculate how much of the treatment dose can reach the lungs to avoid damaging the lungs.
This procedure is often performed on an outpatient basis. However, some patients may require hospitalization after the procedure. Please consult your physician about whether you will be hospitalized.
You may be given medication to prevent nausea and pain, as well as antibiotics to avoid infection.
You will be lying on your back.
You may be hooked up to monitors that track your heart rate, blood pressure, and pulse during the procedure.
A nurse or technologist will insert an IV-system into a vein in your hand or arm so that the sedative can be taken intravenously. Moderate sedation may be used. Alternatively, a full anaesthetic may be given.
The area of your body where the catheter will be inserted (usually the groin area) will be shaved, sterilised and covered with a surgical drape.
Your doctor will numb the area with a local anaesthetic. A very small skin incision will be made at the site.
Using image guidance, a catheter (a long, thin, hollow, plastic tube) is inserted through the skin into the femoral artery, a large groin blood vessel, and guided to the site for treatment.
Once the catheter is inserted into the branches of the hepatic artery that feed the tumour, tiny glass beads or microspheres are injected through the catheter to the site. Over the next 10 to 14 days, radiation will be released from the microspheres anchored in the blood vessels.
At the end of the procedure, the catheter will be removed and pressure will be applied to stop the bleeding. The hole in the skin is then covered with a bandage. No stitches are needed.
The IV system will be taken off.
This procedure is usually completed within one hour.
What Will I Experience during and after the Procedure?
Devices will be attached to your body to monitor your heart rate and blood pressure.
You will feel a slight prick when the needle is inserted into your vein for the infusion system and when the local anaesthetic is injected. Greatest sensation is felt at the site of the skin incision, which is numb from the local anaesthetic. You may feel pressure when the catheter is introduced into a vein or artery.
If the procedure is done with a sedative, the intravenous sedative will make you feel relaxed and sleepy. You may also stay awake, depending on how heavily you would have been sedated.
You may feel slight pressure when the catheter is introduced into your body, but not serious discomfort.
As the contrast agent passes through your body, you may feel a sensation of warmth.
In principle, radioembolization is painless; however, some patients may feel pain briefly when the microspheres are injected. Pain that lasts over six to eight hours means that an ulcer has developed in the patient's stomach or duodenum. These ulcers may be treated like any other ulcers.
You will remain in the recovery room until you are fully awake and ready to go home.
Some patients experience some side effects called post-embolization syndrome, including nausea, vomiting and fever. Pain is the most common side effect as blood supply to the treated area is cut off. It may be controlled with medication taken orally or intravenously.
These side effects usually subside within three to five days and may be relieved medically. You should tell your doctor if symptoms persist for more than seven to 10 days.
You may also experience a mild form of fever, lethargy, and severe fatigue that usually lasts about a week.
You should be able to return to your normal activities within a day or two after the procedure.
During the week after radioembolization, you should limit your contact with others until the radiation from your body is reduced. You should not perform the following activities for at least seven days after the procedure:
- sleep in the same bed as your partner.
- use public transport where you have to sit next to another person for more than two hours.
- come into close contact with children and pregnant women.
Radioembolization may be carried out as part of two separate treatments if the tumours are located on either side of the liver. CT and MRI scans may be performed every three months after treatment to determine the size of the treated tumour.
Who Interprets the Results and How Do I Get Them?
An interventional radiologist may inform you if the procedure was technically successful at the time it is completed.
Your interventional radiologist may recommend a follow-up after the procedure or after the treatment is completed.
The review may include physical examination, diagnostic imaging(s), and blood or other laboratory tests. During the follow-up, you and your doctor may discuss any changes or side affects you have experienced since the procedure or treatment was administered.
What are the Benefits Versus Risks?
Benefits
- For patients with inoperable tumours, radioembolization may extend life by months to years and improve the quality of life. In some cases, it may allow for better treatment options, such as surgery or liver transplant.
- Radioembolization causes fewer side effects than standard radiotherapy.
- No surgical incision is needed – just a small incision that does not need stitching.
- Radioembolization delivers a higher dose of radiation than standard external beam radiotherapy.
Risks
- Any procedure that penetrates the skin carries a risk of infection. The chance of an infection requiring antibiotic treatment is significantly less.
- There is a very small risk of an allergic reaction to the injected contrast agent.
- Any procedure that needs the insertion of a catheter into a blood vessel carries some risks. These risks include damage to the blood vessel, bruising or bleeding from the puncture site, and infection.
- There is a risk that the microspheres may end up in the wrong place, where the patient is at risk of a stomach or duodenal ulcer. This happens with approximately two percent of patients.
- There is a risk of infection after radioembolization, even if an antibiotic is given.
- As angiography is part of the procedure, there is a risk of an allergic reaction to the contrast agent.
What are the Limitations of Radioembolization?
Radioembolization is not recommended in cases of acute hepatic and renal dysfunction, abnormal blood coagulation, or bile duct blockage. In some cases - regardless of liver dysfunction - radioembolization may be performed in small amounts and spread over several treatments in an attempt to reduce the effect on the normal liver.
Radioembolization is a therapy, not a cure. Approximately 70% to 95% of patients will see an improvement in their liver and depending on the type of liver tumour, this may improve survival rates. Multiple studies have shown that up to 95% of patients with colorectal metastases (tumours that have spread) and up to 97% of patients with neuroendocrine tumours benefit from radioembolization.