BACKGROUND: The objective of the current study was to identify patient and disease related factors that influence response and survival for patients with unresectable hepatocellular carcinoma (HCC) who received a systemic combination chemotherapy consisting of cisplatin, alpha-interferon, doxorubicin, and 5-fluorouracil (PIAF). METHODS: From July 1996 to February 1999, 149 patients with unresectable HCC were treated with PIAF: cisplatin (20mg/m2 intravenously, Days 1-4), doxorubicin (40mg/m2 intravenously, Day 1), 5-fluorouracil (400mg/m2 intravenously, Days 1-4), and alpha-interferon (5MU/m2 subcutaneously, Days 1-4), once every 3 weeks up to a maximum of six cycles. Univariate and multivariate analyses of patient and disease characteristics were used to identify factors predicting response and survival. RESULTS: The objective response rate according to conventional criteria was 16.8% (complete response in 3 out of 149 patients, or 2%, 95% confidence interval [CI] 0-4.3%; partial response in 22 out of 149 patients, or 14.8%, 95% CI 9-20%). The median survival time was 30.9 weeks (95% CI 22.1 to 40). Significant independent predictors of an objective response were: absence of cirrhosis (P = 0.006), low bilirubin level (P = 0.006), and positive hepatitis C serology (P = 0.025). The following factors were related to a shorter survival time: high Okuda stage (P = 0.001), vascular involvement (P = 0.018), and cirrhosis (P = 0.008). Good risk patients (absence of cirrhosis and total bilirubin <or = 0.6mg/dL) had an objective response rate of 50%. CONCLUSIONS. Patients with unresectable HCC who also have normal total bilirubin and non-cirrhotic livers have a better chance of response and prolonged survival after treatment with systemic PIAF.