The prognosis for patients with unresectable hepatocellular carcinoma (HCC) tumors is extremely poor. Even in the case of small nodular lesions detected by US screening, patients receiving no treatment showed a mean 3-year survival rate of 12%. Transcatheter arterial chemoembolization (TACE), most frequently performed by intra-arterially injecting an infusion of antineoplastic agents mixed with iodized oil (Lipiodol), has been extensively used in the treatment of large HCC tumors. However, although massive tumor necrosis can be demonstrated in most cases, a complete necrosis of the tumor has rarely been achieved with TACE, since residual tumor can be found in a non-negligible number of the treated lesions. It si, however, useful prior to liver transplantation.
TACE was found mostly effective in nodules less than 4 cm in diameter, with a thick tumor capsule. In fact, small, encapsulated HCC are almost completely fed by hepatic arterial blood and therefore highly responsive to hepatic arterial embolization. On the contrary, in unencapsulated tumors or in tumors showing extracapsular invasion of neoplastic cells, TACE often fails to induce complete necrosis since tumor cells, either unimpeded by the absence of a capsule or spreading across the capsule itself, invade the adjacent liver parenchyma, thus obtaining additional blood supply from the sinusoidal portal system.
Large HCC lesions can be more effectively treated with combined TACE and PEI. In fact, alcohol diffusion is easier after the occurrence of the necrotic changes produced by TACE, thus allowing the intranodular injection of larger amounts of ethanol. Moreover, after arterial embolization, the normal wash-out of the injected ethanol is more difficult in the tumorous area, resulting in longer retention of the substance. The combination of TACE and PEI seems to be a highly effective treatment for large HCC also in the instances when daughter nodules are associated with a main tumor. The presence of the capsule significantly enhances the chances of success and should be considered an important requirement when selecting patients to be submitted to TACE and PEI.
There are no definitive randomized studies but various reviews and meta-analyses suggest that it is effective.
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