Embolization Therapy for Liver Cancer
Embolization is a procedure that injects substances directly into an artery in the liver to block or reduce the blood flow to a tumor in the liver.
The liver is special in that it has 2 blood supplies. Most normal liver cells are fed by the portal vein, whereas a cancer in the liver is mainly fed by the hepatic artery. Blocking the part of the hepatic artery that feeds the tumor helps kill off the cancer cells, but it leaves most of the healthy liver cells unharmed because they get their blood supply from the portal vein.
Embolization is an option for some patients with tumors that cannot be removed by surgery. It can be used for people with tumors that are too large to be treated with ablation (usually larger than 5 cm across) and who also have adequate liver function. It can also be used with ablation. Embolization can reduce some of the blood supply to the normal liver tissue, so it may not be a good option for some patients whose liver has been damaged by diseases such as hepatitis or cirrhosis. It isn’t yet clear which type of embolization has a better long-term outcome.
People getting this type of treatment typically do not stay in the hospital overnight.
Trans-arterial embolization (TAE)
During trans-arterial embolization a catheter (a thin, flexible tube) is put into an artery in the inner thigh through a small cut and eased up into the hepatic artery in the liver. A dye is usually injected into the bloodstream to help the doctor watch the path of the catheter. Once the catheter is in place, small particles are injected into the artery to plug it up, blocking oxygen and key nutrients from the tumor.
Trans-arterial chemoembolization (TACE)
Trans-arterial chemoembolization is usually the first type of embolization used for large liver cancers that cannot be treated with surgery or ablation. It combines embolization with chemotherapy (chemo). Most often, this is done by giving chemotherapy through the catheter directly into the artery, then plugging up the artery, so the chemo can stay close to the tumor.
Drug-eluting bead chemoembolization (DEB-TACE)
Drug-eluting bead chemoembolization combines TACE embolization with drug-eluting beads (tiny beads that contain a chemotherapy drug). The procedure is essentially the same as TACE except that the artery is blocked after drug-eluting beads are injected. Because the chemo is physically close to the cancer and because the drug-eluting beads slowly release the chemo, the cancer cells are more likely to be damaged and die. The most common chemo drugs used for TACE or DEB-TACE are mitomycin C, cisplatin, and doxorubicin.
Radioembolization combines embolization with radiation therapy. This is done by injecting small beads (called microspheres) that have a radioactive isotope (yttrium-90) attached to them into the hepatic artery. Once infused, the beads lodge in the blood vessels near the tumor, where they give off small amounts of radiation to the tumor site for several days. The radiation travels a very short distance, so its effects are limited mainly to the tumor.
Possible side effects of embolization
Possible complications after embolization include:
Sometimes, it can take 4-6 weeks to fully recover from the procedure. Because healthy liver tissue can be affected, there is a risk that liver function will get worse after embolization. This risk is higher if a large branch of the hepatic artery is embolized. Serious complications are not common, but they are possible.