Changes In Atenuation After Radiofrequency Ablation. Relationship With Local Recurrence In Hepatocellular Carcinoma

Objective: Know if differences in attenuation before and after radiofrequency ablation (RFA) are different in subjects with local recurrence and those that maintain complete response during the irst 6 months.Methods and materials: Retrospective study from March 2008 to September 2009. All patients with Hepatocellular carcinoma Stage A of Barcelona Clinic Liver Cancer (BCLC) that were treated with RFA were included. Patients in which RFA was guided by ultrasound were excluded; also patients that did not have pre and post ablation CT taken on the same day were not included. Hounsield units (HU) were measured pre and post-RFA and a delta was calculated. At 6 month follow up local recurrence was evaluated based on imaging criteria for tumor response (mRECIST). A local recurrence was deined as an active lesion in a previously treated region. An active lesion must have arterial enhancement and washout. Student's t was used to compare the attenuation change between patients with local recurrence and those that maintained complete response.Results: Twenty ablation procedures in twenty patients were included. Seven patients had local recurrence at 6 months (35%). In this group, mean delta was 3.86 HU. In the group of patients that maintained complete response (65%;n=13) the mean change in attenuation was 15.18 HU (p=0.02).Conclusion: The difference in attenuation (delta) pre and post-RFA, measured the same day of ablation, is different between patients with local recurrence at 6 month and those that continue with complete response during follow up. These results are applicable to patients with early hepatocellular carcinoma.