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

Background 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.