Hepatocellular carcinoma (HCC) most common type of primary liver cancer is a leading cause of death in the world. Transarterial radioembolization is a transcatheter intra-arterial therapy with yttrium-90 (Y90), used to treat primary and secondary liver malignancies. It is performed by an interventional radiologist, has become increasingly popular in the treatment of HCC.
What is Radioembolization?
Radioembolization is a combination of radiation therapy and a procedure called embolization to treat cancer of the liver. It is one of the types of Nuclear Medicine Therapy.
Embolization is a minimally invasive method that combines embolization and radiation therapy. Tiny glass or resin beads containing the radioactive isotope yttrium Y-90 are inserted into the tumor’s blood arteries.
Radiation therapy is the process of eliminating cancer cells and shrinking tumors by using a specific type of energy termed ionizing radiation. Unlike external beam therapy (EBT), which involves directing high-energy x-ray beams from outside the body towards the tumor, radioembolization involves injecting a radioactive material directly into the body. This form of treatment is called internal radiation therapy.
To restrict the supply of blood to cancer cells, microscopic glass or resin beads called microspheres are inserted inside the blood arteries that feed a tumor during radioembolization.
These microspheres, which are loaded with the radioactive element yttrium Y-90, become trapped at the tumor site and give a high dosage of radiation to the tumor while conserving normal tissues.
About yttrium – 90 (Y-90)?
The chemical element yttrium seems to have the symbol Y and the atomic number 39. It is a silvery-metallic transition metal that is chemically related to the lanthanides and is frequently referred to as a “rare-earth element.”
Yttrium-90 is a radioactive isotope, therefore it emits radiation when it decays. Radiation is a form of energy that can cause damage to cancer cells, including tumors, to be shrunk, or killed. S surgeons use microspheres, which are unique glass or resin pellets with yttrium-90 embedded in them, to distribute this radiation.
How Does Equipment Look Like?
X-ray guidance is commonly used for radioembolization operations including the following steps:
This method involves the use of X-ray equipment, a catheter, microspheres, or microscopic glass beads loaded with the radioactive yttrium-90.
A radiography table, one or two x-ray tubes, and a video monitor are commonly used in this procedure. Fluoroscopy is the process of converting x-rays into video pictures. It is used by doctors to monitor and guide surgeries. The video is created by an x-ray machine and a detector suspended over the exam table.
A catheter is a long, thin plastic tube that looks like a pencil lead but is much smaller. It has a diameter of roughly 1/8 inch.
The ionizing radiation is delivered via millions of glass beads, each of which is tiny than human hair and weighs roughly half a teaspoon.
An intravenous line (IV), an ultrasound machine, and gadgets to monitor your heart rate and blood pressure may be used during this treatment.
What is the Mechanism of Action?
The interventional radiologist uses x-ray imaging and contrast material to visualize the blood vessels before inserting a catheter through the skin into a blood vessel and advancing it to the treatment location. The radiation-filled microspheres, also known as glass beads, are subsequently introduced into the tumor’s blood arteries through the catheter.
Once lodged in the tumor site, the microspheres give a significant dose of radiation to the cancer cells. The microspheres will stop blood from flowing to the tumor, depleting the malignant cells of oxygen and nutrition.
The liver is supplied with blood via two main blood arteries.
The portal vein supplies around 75% of the blood flow to normal liver tissue, while the hepatic artery and its branches supply about 25 percent. The hepatic artery provides practically all of the blood flow to a tumor growing in the liver.
Because radioactive microspheres are supplied through the hepatic artery, they directly reach the tumor while preserving the majority of healthy liver tissue.
Over a two-week period, the radiation from yttrium-90 gradually declines and then vanishes after 30 days. The small microspheres do not cause any complications in the liver.
How Patient is Prepared For The Procedure?
Following steps will be taken by an expert before performing the procedure:
You will have an office consultation with the interventional radiologist who will perform your operation a few days before the procedure.
Your doctor may test your blood before your procedure to monitor kidney function and see if your blood clots normally.
Seven to ten days before your procedure, you will have an angiography, which will create images of the blood vessels feeding the tumor.
Because your interaction with children and adults may be restricted for three to seven days after your surgery, you may need to make arrangements for your return to home.
Tell your doctor about all of your prescription and over-the-counter medications, as well as any herbal supplements you’re taking. Any allergies, especially to local anesthetics, general anesthesia, or contrast agents, should be noted. Before your procedure, your doctor may advise you to stop taking aspirin, nonsteroidal anti-inflammatory medicines (NSAIDs), or blood thinners.
Inform your doctor about any recent illnesses or medical problems.
If a woman is pregnant, she should always tell her doctor and technician to avoid exposing the fetus to radiation, doctors will not do many tests during pregnancy. If an x-ray is required, the doctor will take care to limit the baby’s exposure to radiation.
You will be given precise instructions on how to prepare, including any adjustments to your regular medication routine that may be required.
For the procedure, you will be given a sedative. Before the treatment, you will be given particular instructions on what to eat and drink, and you will need a relative or friend to join you and drive you home.
What Happens After The Procedure?
The patient is usually required to stay in the hospital for two to three days following the Transarterial Radioembolisation procedure, primarily because the radioactive material administered to the patient yields him radioactive for a period of time, and he must be kept in relative isolation to protect the attendants and the general public from unnecessary radiation exposure.
What Are The Response Rate of TARE Therapy?
Response rates are affected by a number of factors, including whether the tumors are original liver malignancies or secondary cancers. The size of the tumors, the extent to which the tumor has spread throughout the liver, the tumor biology, and the patient’s overall health are all factors to be considered. All of these aspects are taken into account when treating patients. To ensure that best clinical practice guidelines are followed, each case is discussed in a multidisciplinary tumor board comprised of medical oncologists, radiation oncologists, and surgeons.
Instructions From Doctor
The interventional radiologist will tell you whether the procedure was successful or not after it is completed.
A follow-up appointment may be recommended by your interventional radiologist.
A physical exam, imaging exam, and blood tests may be performed during this visit. Tell your doctor if you will observe any side effects or changes during your follow-up visit.
Benefits of Transarterial Radioembolisation Therapy
Radioembolization can extend the lives of patients with inoperable malignancies from months to years and enhance their quality of life. It may open the door to more curative treatments, such as surgery or liver transplantation, in some patients.
When compared to traditional radiation therapy, radioembolization has minimal adverse effects. There is no need for a surgical incision, only a little scratch in the skin that does not require stitching.
Radioembolization delivers a larger dosage of radiation to the tumor than regular external beam therapy or any other nuclear medicine therapy.
Side Effects of Therapy
Infection is a possibility with any surgery that enters the skin. Infections requiring antibiotic therapy appear to be rare, with a chance of less than one in 1,000 people.
If contrast material is injected during the procedure, there is a small chance of an allergic reaction.
Any procedure that involves inserting a catheter into a blood vessel carries some risk. Damage to the blood vessel, bruising or bleeding at the puncture site, and infection are all concerns. To reduce these dangers, the doctor will take required precautionary steps.
There is a chance that microspheres will end up in the wrong spot, putting the patient at risk for a stomach or duodenal ulcer. Approximately 2% of patients experience this hazard.
Even if an antibiotic has been provided, there is a danger of infection after radioembolization.
There is a possibility of an adverse reaction to the contrast substance because angiography is part of the process.
It is important to note that radioembolization is a treatment, not a cure. In about 70 to 95 percent of patients, the liver will heal, and depending on the kind of liver cancer, survival rates may improve. According to multiple studies, radioembolization helps up to 95 percent of patients with colorectal metastases (tumors that have spread) and up to 97 percent of patients with neuroendocrine tumors.