Transarterial chemoembolization for hepatocellular carcinoma over three decades: current progress and perspective.

Transcatheter arterial chemoembolization has been performed worldwide for patients with unresectable hepatocellular carcinoma for three decades. After long controversy, survival benefit was revealed by two randomized controlled trials. In Japan, chemoembolization accounted for initial treatment of 32% of patients and 58% for recurrent foci. The indications of chemoembolization are various: they are multinodular tumors in the Barcelona Clinic Liver Cancer staging system and two or three tumors >3 cm or four or more tumors in the Japanese guidelines, and both indications fulfill the Child-Pugh Class A/B or liver damage A/B and exclusion of vascular invasion or extrahepatic spread. Recently, both guidelines were identified to have almost similar content. The 4966 patients stratified to chemoembolization recommended by the Japanese guidelines showed that 3-year survival of patients with two or three tumors >3 cm or four or more tumors was 55 and 46% in Child-Pugh A, respectively, and 30 and 22% in Class B, respectively. These results would help in comparing the outcome of chemoembolization in the different backgrounds of the East and West. The modified Response Evaluation Criteria in Solid Tumor guideline is now proposed to cover the deficiency of Response Evaluation Criteria in Solid Tumor to evaluate the response to chemoembolization. Recently, chemoembolization with drug-eluting beads and radioembolization with yttrium-90 microspheres have been introduced, and each of them showed similar tumor response and median survival compared with conventional chemoembolization. Moreover, the combination of chemoembolization and molecular targeted agent is now on-going to evaluate the synergistic effect.