Prediction Model for Intrahepatic Distant Recurrence After Radiofrequency Ablation for Primary Hepatocellular Carcinoma 2 cm or Smaller.

Background: Intrahepatic hepatocellular carcinoma (HCC) has a high recurrence rate after radiofrequency ablation (RFA). However, to date, no standalone predictive factors for intrahepatic distant recurrence after curative ablation have been reported.

Aims: The aim of this study was to investigate predictive factors for intrahepatic distant recurrence after curative treatment with RFA for HCCs.

Methods: This multicenter study consisted of 17 institutions that registered 821 patients. The risk factors for intrahepatic distant recurrence after complete ablation by RFA for primary HCC ≤ 2 cm in diameter were identified in a retrospectively collected training set (n = 636) and then validated in a prospectively collected validation set (n = 185).

Results: The cumulative intrahepatic distant and local recurrence rates (i.e., entire recurrence rate) in the training set were 23.6% and 53.7% at 1 and 3 years, respectively. The cumulative intrahepatic distant recurrence rates in the training set were 17.0% and 43.8% at 1 and 3 years, respectively. Multivariate analysis of the training set showed that tumor number and serum levels of α-fetoprotein (AFP) and des-γ-carboxy prothrombin (DCP) were independent risk factors for both entire recurrence and intrahepatic distant recurrence. Intrahepatic distant recurrence risk in both the training and validation cohorts was stratified using a scoring system with three factors: tumor number (single or multiple), AFP (< 10 ng/ml or ≥ 10 ng/ml), and DCP (< 50 mAU/ml or ≥ 50 mAU/ml).

Conclusion: The scoring system composed of tumor number, AFP, and DCP is useful for classifying the risk of intrahepatic distant recurrence after curative ablation for HCC.