Chemoembolization for unresectable hepatocellular carcinoma in Japan.

Of 15,681 patients with hepatocellular carcinoma (HCC), 30% underwent transcatheter arterial chemoembolization with lipiodol (Lip-TACE) including infusion chemotherapy with lipiodol (Lip-TAI) for the initial treatment, and 58% underwent it for recurrent HCC according to the latest biannual report of the Liver Cancer Study Group of Japan (LCSGJ). Superselective Lip-TACE is considered to be indispensable to maximize the therapeutic effect (TE) and to minimize injury to the non-cancerous liver. The local recurrence rate of a single session Lip-TACE for HCC <or=5 cm in diameter ranged from 33 to 38% at 3 years. A pathologic study using resected specimens of 26 HCCs treated by Lip-TACE showed that the mean necrosis rates and frequency of complete necrosis in three groups, small (<or=3 cm, n = 6 HCCs), medium (3.1-5 cm, n = 10), and large size (>or=5.1 cm, n = 10) were 95, 87.1%; 68.4, 66.7%; 30, 0%, respectively. Namely, the smaller the tumor size, the higher the TE. However, Lip-TAI showed no correlation between TEs and tumor size. A comparative study between the pathologically proven necrosis rate on the maximum cut surface of the lesion and radiologic necrosis estimated by CT showed a significantly good correlation when the lipiodol-retained area was presumed necrotic, but a poor correlation when it was presumed a viable one. No correlation was seen between the pathologic necrosis rate and the decreased rate of the lesion treated by Lip-TACE assessed by WHO criteria. The modified version of the assessment criteria of the TE of treatment for liver cancer was proposed by the LCSGJ in 2009, using a 4-grade treatment effect with two factors of tumor necrosis and tumor regression.