Our uncontrolled phase I1 study was aimed at assessing the efficacy of transarterial embolization in patients with hepatocellular carcinoma and to determine the parameters associated with a favorable response to treatment, improved survival or both. Fifty consecutive patients (25 corresponding to Okuda's stage I and 25 to stage 11) with hepatocellular carcinoma (41 being multinodular or massive) were included. Transarterial embolization induced a selflimited postembolization syndrome that was well tolerated. Nevertheless, three patients died shortly after the procedure because of tumor progression (two cases) or progressive liver failure. A favorable response (extensive necrosis with reduction of tumor area greater than 50%) was achieved in 81% of the cases, and this result was independently (p < 0.05) related to a preserved performance status and to a lower alphafetoprotein concentration. The survival of the patients at 1 and 2 yr was 65% and 38%, respectively, better than the expected survival according to a mathematical model obtained from a historical series of untreated cases (42% and 20%, respectively). Cox regression analysis disclosed that both a favorable therapeutic response and a preserved physical condition (reflected by performance status of 0 or 1) were independently associated with better survival (regression coefficient -2.248 and 0.869, respectively). These data indicate that transarterial embolization has a marked antitumoral effect in patients with inoperable hepatocellular carcinoma and that the therapeutic success is asso- ciated with improved survival. Nevertheless, because