Marginal Recurrence after Radiofrequency Ablation of Hepatocellular Carcinoma: Relationship between Distance from Hepatic Capsule to Tumor and Recurrence Period

ABSTRACT

PURPOSE: To examine the relationship between distance from hepatic capsule to tumor and recurrence among hepatocellular carcinoma patients in whom marginal recurrence was noted after radiofrequency ablation therapy. MATERIALS AND METHODS: Between January 2000 and December 2001, hepatocellular carcinoma patients with a tumor 5 cm or less in size and located 2 cm or less from the hepatic capsule underwent radiofrequency ablation therapy. We subsequently selected 37 patients (41 tumors) in whom immediate CT demonstrated complete tumor ablation and follow-up CT showed marginal recurrence. Tumors were grouped according to their distance from the hepatic capsule Group I, adhered to the capsule; Group II, less than 1 cm from it; Group III, 1-2 cm distant. Of the 41 tumors, 22 were assigned to Group I, six to Group II, and 13 to Group III. Mean tumor size was 3.2 cm, and inter-group variation was small (Group I, 3.3 cm; Group II, 2.9 cm; Group III, 3.1 cm). Follow-up CT was used to determine marginal recurrence, and for inter-group comparison and the assessment of statistical significance, the t test was employed. RESULTS: Marginal recurrence was noted at mean 5.5 months (2.7 months in Group I, 3.0 months in Group II, and 10.5 months in Group III). The t test revealed significant difference between Group I and III (p<0.0001) but not between Groups I and II, or II and III. If '1 cm from hepatic capsule' was the criterion for classification, and Group I and II were combined and compared with Group III, there was significant difference between the two groups (<0.0001). CONCLUSION: Tumors which adhered to the hepatic capsule or were less than 1 cm from it recurred sooner than those situated 1-2 cm away.