There is no standard treatment for patients with unresectable hepatocellular carcinoma (HCC). Survival benefits derived from medical interventions are controversial. The aim of this systematic review was to assess the evidence of the impact of medical treatments on survival. Randomized controlled trials (RCTs) that were published as full papers assessing survival for primary treatments of HCC were included. MEDLINE, the Cochrane Library, CANCERLIT, and a manual search from 1978 to May 2002 were used. The primary end point was survival, and the secondary end point was response to treatment. Estimates of effect were calculated according to the random effects model. Sensitivity analysis included methodological quality. We identified 61 randomized trials, but only 14 met the criteria to perform a meta-analysis assessing arterial embolization (7 trials, 545 patients) or tamoxifen T he incidence of hepatocellular carcinoma (HCC) is increasing worldwide. 1 Liver cancer is the fifth most common cancer in the world and the third most common cause of cancer-related death. 2 Cohort studies and cost-efficiency modeling have suggested that surveillance of well-defined cirrhotic patients may decrease tumor-related mortality. However, only 30% of patients benefit from curative therapies such as resection, transplantation, or percutaneous ablation 3 and achieve 5-year survival rates of 50% to 75%. 4 Most patients with HCC are diagnosed at intermediate to advanced stages, and there is no standard treatment for these patients. 3,4 The most reliable method to show survival advantages is to perform large randomized controlled trials (RCTs) that include more than 1,000 patients comparing treatment versus no treatment in a well-defined strata of individuals. 5-10 These investigations are lacking in patients with HCC. On the contrary, several medical interventions have been tested in the setting of small RCTs. However, the reduced size of these studies may cause questions of their statistical power when detecting survival differences, which, as in many areas of health care and oncology, are unlikely to be large. This raises the need for a systematic meta-analysis assessment, with a major role to integrate valid information and provide estimates of treatment effects when RCTs themselves are not of sufficient size. 9,10 Two systematic reviews published years ago 11,12 suggested a potential benefit for at Abbreviations: HCC, hepatocellular carcinoma; RCT, randomized controlled trial; OR, odds ratio; CI, confidence interval.