Ablation for hepatocellular carcinoma: Validating the 3-cm breakpoint.

Abstract

277 Background: Although many previous studies on ablation outcomes for hepatocellular carcinoma (HCC) have dichotomized tumor size around a 3cm cutoff to determine prognostic significance, a growing number of reports describe excellent outcomes for larger tumors. To address the sensibility of this somewhat arbitrary 3-cm cutoff, we stratified patients by 1cm tumor size intervals and hypothesized that disease-specific survival (DSS) would not vary significantly between adjacent groups. Methods: Patients treated with local ablation for T1 HCC (≤8cm) were identified from the Surveillance, Epidemiology, and End Results database (2004-2008). Log-rank tests were used to compare DSS curves of adjacent study groups, and multivariable Cox proportional hazards models were used adjust for confounding variables. Results: There were 1,093 patients included in the study (26% female, median age: 62 years). The 3-year DSS was significantly lower in patients with 3-4cm tumors compared to 2-3cm tumors (58% vs 72%, p=0.002, Table). In adjusted models, DSS did not vary significantly between any size intervals up to 3cm. Patients with 3-4cm tumors, however, had a poorer prognosis compared to patients with 2-3cm tumors (hazard ratio: 1.60, 95% confidence interval: 1.18-2.18, p=0.002). DSS also fell significantly when tumor size increased from 5-6cm to 6-7cm (53% vs 21%, 0.006). Age and alpha-fetoprotein levels were also independently predictive of DSS in most multivariable models; however, the presence or absence of cirrhosis was not predictive in any models (smallest p=0.382). Conclusions: This study defends the use of a 3cm breakpoint when studying outcomes after ablation for HCC. Although some have advocated that ablation is more successful in cirrhotics, we found no evidence for this in our study. [Table: see text]