Embolization is a treatment that uses a material, agent or tiny beads (microspheres) to block a tumour’s blood supply. When the embolization beads are combined with chemotherapy drugs, it is called chemoembolization. Transarterial chemoembolization (TACE) is a specific type of chemoembolization in which the beads and drugs are injected into the hepatic artery.
Hepatocellular carcinoma, the most common type of primary liver cancer, grows a large number of blood vessels. These blood vessels get most of their blood supply from the hepatic artery, while the rest of the liver tissue gets blood from the portal vein. Because of this, doctors can cut off the blood supply to the tumour, while preserving as much of the remaining liver tissue as possible.
TACE may be used to shrink and control liver cancer tumours in people who:
- have tumours that cannot be removed by surgery
- In rare cases, it may be used to shrink a larger tumour so it can be removed by surgery.
- have cancer that has not spread beyond the liver
- have good liver function and do not have any problems with the portal vein
- cannot have a liver transplant
- are waiting for a liver transplant (“bridging” therapy)
People with liver cancer may not be able to have TACE if they have:
- poor liver function
- People who have poor liver function may be offered embolization treatment without chemotherapy.
- problems with the portal vein, such as:
- tumour invasion
- increased pressure (portal hypertension)
- blood clots in the vein (portal vein thrombosis)
- abnormal buildup of fluid in the abdomen (ascites)
- bleeding veins (varices) in the esophagus
- a reduction in the number of all types of blood cells (pancytopenia)
Tumours larger than 5 cm can be treated with TACE, but it may take 2 or 3 treatments to shrink a large tumour. If the cancer is in both lobes of the liver, each lobe will be treated at different times. Treatment to each lobe is usually given a month apart so the person with cancer has time to recover from the first treatment.
TACE is done in the x-ray department of a hospital. The person is given a local anesthetic along with a drug to help them relax (sedation), or a general anesthetic.
A thin tube (catheter) is placed into the large blood vessel in the groin (femoral artery). The catheter is then moved up through the artery until it reaches the hepatic artery in the liver. A radioactive dye is injected into the catheter and an x-ray (angiogram) is taken to find the branches of the artery that are feeding the liver tumour. The catheter is then moved to these arteries.
The arteries are blocked by injecting materials or tiny beads (microspheres) into them. The most commonly used material for TACE is a gelatine sponge. Sometimes the gelatine sponges are soaked in a chemotherapy drug and an oily liquid called lipiodol before being placed into the artery. The sponge traps the chemotherapy drugs inside the liver so that it is concentrated in the area of the tumour(s). Lipiodol lengthens the amount of time that the drugs are held in the liver. The embolization may be temporary (the blocking material dissolves) or permanent.
Chemotherapy drugs are injected into the arteries after they are blocked. The drugs that are most commonly used for TACE are:
- doxorubicin (Adriamycin) – the most commonly used
- cisplatin (Platinol AQ)
- 5-fluorouracil (Adrucil, 5-FU)
- mitomycin (Mutamycin)
For information on specific drugs, go to sources of drug information.
If the cancer is in only one lobe of the liver, a small amount of chemotherapy may be given to the other lobe to treat any undetected tumours.
After the chemoembolization is delivered, the catheter is withdrawn back through the femoral artery. Pressure and ice are placed over the incision to help reduce swelling and stop bleeding.
A computed tomography (CT) scan may be done after 2 or 3 months to see how much tumours have shrunk and to look for any new tumours in the liver.
Many people will need another TACE procedure because the tumours eventually grow back, most often in 10–16 months. TACE can be repeated as many times as necessary, as long as the person with liver cancer remains healthy enough to have the procedure.