Transcatheter arterial chemoembolization


 * This article is about a medical procedure. See also Tumor Necrosis Factor Alpha Converting Enzyme

Transcatheter arterial chemoembolization (TACE) has been used extensively in the palliative treatment of unresectable HCC (hepatocellular carcinoma), one of the most common malignancies worldwide.

In the west, the most common causes are alcoholic and viral (hepatitis C) hepatitis. The standard treatment for HCC is surgical resection, which has a 60% 5-year survival. In cases of unresectable tumor or marginal liver function, the current treatment of choice is orthotopic liver transplantation. Due to the scarcity of organ donors and to the multiple comorbidities these patients have, many die while on the transplant list.

TACE also has a role in delaying the progression of HCC until a donor liver becomes available.

With continuing TACE, the lifespan for a patient with unresectable HCC could reasonably be extended for 1-2 years (although the exact benefit would depend heavily on the patient's medical condition (see Child-Pugh score).

Procedure
TACE is an interventional radiology procedure. The procedure involves gaining percutaneous access to the hepatic artery, usually by puncturing the common femoral artery in the right groin and passing a catheter through the abdominal aorta, through the celiac axis and common hepatic artery, into the proper hepatic artery (which supplies the liver).

The interventional radiologist then performs an arteriogram to identify the branches of the hepatic artery supplying the tumor(s) and threads smaller catheters into these branches. This is done to maximize the amount of the chemotherapeutic dose that is directed to the tumor.

When a blood vessel supplying tumor has been selected, alternating aliquots of the chemotherapy dose and of embolic particles are injected through the catheter. The total chemotherapeutic dose may be given in one vessel's distribution, or it may be divided among several vessels supplying the tumor(s).

TACE derives its beneficial effect by two methods. Since most tumors are supplied by the hepatic artery, arterial embolization interrupts their blood supply and postpones growth until replaced by neovascularity. Secondly, focused administration of chemotherapy allows a higher dose to the tissue while simultaneously reducing systemic exposure, which is typically the dose limiting factor. This effect is potentiated by the fact that the chemotherapeutic drug is not washed out from the tumor bed after embolization.

Complications
As with any interventional procedure, there is a small risk of hemorrhage and/or damage to blood vessels.

The goal of the procedure is to kill tumor. The resulting necrotic material releases cytokines and other inflammatory chemicals into the blood stream, and patients are routinely kept in a hospital for 1 to several days following the procedure.

A concerning complication of TACE is the development of an abscess within the necrotic tissue. This is a potentially fatal event.