Transcatheter arterial chemoembolisation

Cone-beam CT

during TACE: a useful tool!. CT (arterial phase): mild hypervascular nodule in the segment 4.

Transarterial chemoembolisation therapy (TACE) is a localized method of administrating chemotherapy directly to a liver tumor via a catheter study. The chemoembolic agent may be delivered via a mixture with LipiodolⓇ, known as conventional TACE, or as an injection of drug-eluting beads (DEB-TACE).

Transarterial embolization (TAE) (i.e. without a chemotherapy agent added) is also used, and there is evidence that this may be just as effective as TACE.

Indications

TACE is most commonly used in the treatment of hepatocellular carcinoma (HCC) and selective metastatic disease (most commonly from colorectal carcinoma). It may also be used in cholangiocarcinoma .

It can be used as a palliative treatment for a patient with unresectable HCC (usually BCLC stage B) or as a bridge to a liver transplant. It may sometimes also be performed prior to radiofrequency tumor ablation.

Contraindications

Absolute contraindications:

extensive tumor infiltration throughout the liver
encephalopathy
large burden of extra-hepatic metastases

Relative contraindications:

portal vein thrombosis
liver or renal failure
uncorrectable coagulopathy
significant arteriovenous shunting of blood through the tumor

Procedure

Chemoembolic particles are used to occlude hepatic arterial supply to the tumor with resultant necrosis. There is wide variability in the type of embolization particles and chemotherapy, as well as timing .

Outcomes

TACE has been shown to have a survival benefit over current treatments as well as reducing patient symptoms and preventing tumor growth .

CT is typically used for follow up imaging, with the oily based embolic particles having a distinct high attenuation appearance.

One key advantage is the chemotherapy is targeted locally so reducing the systemic side effects of intravenous chemotherapy.

Response to treatment

Imaging is generally advised after 3-4 weeks, either triple phase CT, dynamic MRI or contrast enhanced USG. The accumulation pattern of the iodised oil and enhancement pattern of the mass is to be observed to evaluate the response to the treatment. The more the accumulation greater the necrosis and, thus, the survival. Enhancing areas of tumor are considered as residual viable tumor.

There are four types of patterns that have been described:

type 1
- homogeneous accumulation of iodised oil in the whole tumor and the surrounding area. This type of accumulation indicates good response to treatment
type 2
- homogeneous accumulation of iodised oil in the tumor only
type 3
- irregular accumulation with filling defects. This accumulation represents less than optimal
type 4
- no accumulation/retention of iodised oil