TACE therapy, which in conventional oncology means palliative treatment of tumor-induced liver disease, has a potential often curative impact during the treatment of neuroendocrine tumors

TACE often is the only therapy for the treatment of otherwise unaccessible symptoms of hormone-induced symptoms from neuroendocrine tumors (e.g. "hypoglycemia" in malignant insulinoma). Principally the primary tumor should have been removed surgically if possible.

Liver metastases of tumors receive their blood supply through main liver arteries.

This is obvious in the mostly hypervascularized metastases of neuroendocrine tumors (NET). The hepatic arterial vessels supply only 30 % of total oxygen to the liver, 70% are supplied via the portal vein (V. portae). The liver tolerates "artificial infarction" by embolisation of single segments (partially selective), embolisation of the entire right or left lobe or even the whole liver with the response of a transient postembolisation-syndrome.

Liver embolisation in oncology is applied in various malignant underlying diseases with different success rates (e.g. hepatocellular carcinoma, HCC). This tumor, however, is the prototype of an aggressive tumor growing by destructive infiltration, rapidly causing attenuation of the liver function.

Metastases of neneuroendocrine tumors, which grow slowly and mostly by pushing aside normal liver tissue, do not regularly attenuate liver function and therefore are candidates for embolisation therapy.

Often in endocrine active metastases a specific marker is available for immediate evaluation of a therapeutic success (e.g.blood glucose or serum insulin in malignant insulinoma). The physician does not have to rely solely on imaging material in order to evaluate changes in size or the quality of embolised lesions.

Due to different materials used for embolisation, but especially due to largely differing proliferation rates of tumor vessels in individual tumors, success of an embolisation may last for several weeks only, sometimes months or even years. Repetitions of the TACE treatments are possible, often necessary and also indicated in the presence of only minimal lesions with curative potentia.l

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1. After puncture of the femoral artery (A. femoralis) a catheter is placed via the aorta into the celiac artery with the origin of the main liver artery, where an overview angiographic image is taken (celiacography).Afterwards the catheter is placed into the main right or left liver artery and hence into specific smaller branches depending upon the visualized lesions.

2. If additional chemotherapy is planned the drug is applied intraarterially and transhepatically, reaching the lesions selectively in high concentrations. Severe side effects of certain drugs used (e.g. nephrotoxic effects of streptozotocin) may thus be minimized.

3. Thereafter, blood vessels supplying lesions or metastases are embolized by means of injecting polymeric particles or microspheres (e.g. CONTOUR®-PVA; BostonScientific Co., EMBOSPHERES®) with a known diameter in the µm-range (mesh . Sometimes modern tissue glues such as n-butylcyanoacrylate (NBCA) may be used.

Fat containing emulsions (Lipiodol ®) or alcohol injections have been used, but mostly with transient success.

4. Several groups reverse the course of treatment by firstly partially embolizing specific vessels before applying the chemotherapeutic drug in the hope to further increase the concentrations and prolong the time of local action. It is unknown if this is the case physically.

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