Radiofrequency ablation for hepatocellular carcinoma: the relationship between a new grading system for the ablative margin and clinical outcomes

In our previous study, we classified the radicality (R grading) of percutaneous radiofrequency ablation (RFA) therapy for single hepatocellular carcinoma (HCC) according to the extent of the ablated margin, and demonstrated that this grading system was useful for predicting local tumor progression (LTP) after RFA. The aim of this study was to measure the overall survival (OS), the recurrence free survival (RFS), and the distant recurrence (DR) rate for each R grade (A-D), and to examine the relationship between clinical outcome and R grading. This study involved 368 patients with solitary HCC who had undergone RFA. The mean tumor diameter was 2.0 +/- A 0.7 cm. We calculated the post-RFA cumulative OS, RFS, and DR rate for each R grade and analyzed the factors contributing to clinical outcomes. In the multivariate analysis, significant factors were as follows: tumor size > 2 cm, serum albumin > 3.5 g/dL, prothrombin time > 70 %, HCC recurrence within 1 year, and R grading (grade A) in OS; cause of liver disease (hepatitis B), gamma glutamyl transpeptidase (GGT) > 80 IU/L, platelet count > 10 x 10(4)/mm(3), and R grading (grade A or B) in RFS; GGT > 80 IU/L, platelet count > 10 x 10(4)/mm(3), and R grading (grade A or B) in DR. In patients with sufficient Lipiodol accumulation (n = 219), very similar results were obtained. However, in patients with grade A and B (n = 232), R grade was not a significant independent factor linked to OS, although grade A patients had lower LTP rate. Our proposed R grading system appears to be useful for predicting clinical outcomes after RFA.