Embolization is a procedure that prevents or delays the supply of blood to tissues or to an organ. It can be used to block blood flow to a tumour in order to kill the cancer cells. It is called chemoembolization when the substance used to block the blood supply also transfers chemotherapy drugs to the tumour. Transarterial chemoembolization (TACE) is a specific type of chemoembolization that blocks the hepatic artery to treat liver cancer.
The most common type of primary hepatic cancer is hepatocellular carcinoma (HCC). A large number of blood vessels develop through this form of tumour. Such blood vessels get most of their blood supply from the hepatic artery, while blood from the portal vein gets from the rest of the liver tissue. Because of this, doctors can block the hepatic artery without affecting the rest of the liver to cut off blood supply to the tumour.
If you have strong liver function, you don’t have any fluid in your abdomen (called ascites) and there are no complications with the portal vein in your liver, the health care team will only prescribe TACE. TACE may be used if your liver cancer can not be removed with surgery but has not spread to the major blood vessels in the liver, lymph nodes or other body parts. If you are undergoing a liver transplant (called “bridging” therapy) you may also be given TACE to keep a liver tumour low.
Doctors may offer TACE to treat liver tumors larger than 5 cm but shrinkage of these tumors may take 2 or 3 treatments. If there is cancer in both liver lobes, then doctors will treat one lobe at a time. Treatment for each lobe is usually given a month apart so you’ll have time to recover from the first treatment with TACE.
How TACE is done
TACE is performed within a hospital’s x-ray department. With a drug, you may get a local anesthetic to help you relax, or you may get a general anesthetic to put you to sleep.
The doctor puts a thin tube (called a catheter) inside the vagina (called the femoral artery) in the large blood vessel. Afterwards, the doctor pushes the catheter up through the artery until it hits the liver artery. The catheter is injected with a radioopaque dye and an x-ray is taken to identify the branches of the artery that feed the liver tumor (called an angiogram).
The doctor then transfers certain arteries to the catheter. The doctor injects a drug into the arteries, feeding the tumour.
A gelatin sponge is the most widely used material for the TACE. The gelatin sponge is sometimes soaked in a chemotherapy drug, and an oily liquid called lipiodol before it is inserted into the artery by the doctor. The sponge traps the drugs of chemotherapy inside the liver to concentrate them in the tumor region. Lipiodol prolongs the time the medications are kept in the liver. If the chemotherapy drugs aren’t in the tube, they will be pumped into the arteries following blockage.
DEB-TACE is a new way in which chemotherapy is administered during TACE. This uses special beads with the chemotherapy drug (called drug-eluting beads, or DEBs) already in them. Upon inserting these beads into the arteries in the liver, they slowly release the drug to treat the tumour. These drug-eluting beads are as efficient as sponge use or injection into the arteries of chemotherapy drugs. DEB-TACE can have fewer side effects compared with other approaches.
If the cancer is found in just one lobe of the liver, doctors may give the other lobe a small amount of chemotherapy to treat any tumors that may be present in it.
The doctor takes the catheter out through the femoral artery once the chemoembolization is completed. Pressure and ice over the incision are applied to help reduce swelling and stop bleeding.