Abstract No. 155 Thermal Ablation of Hepatocellular Carcinoma: Does It Matter Whether You Use Heat or Cold?

Thermal ablation is a well-established treatment for hepatocellular carcinoma (HCC). Two of the common forms of thermal ablation are cryoablation (CA) and microwave ablation (MWA). While they have both been established as effective treatment methods, each with strengths and weaknesses, minimal data is available to compare these two modalities. This is of interest given the difference in cell death mechanisms employed by each device. The purpose of this study was to compare the oncologic outcomes and complications in HCC patients treated with MWA and CA. Consecutive patients with HCC who were treated with either CA or MWA at a single academic institution were retrospectively reviewed. Radiologic response per mRECIST, local time to progression (TTP), overall TTP, and overall survival were recorded and taken from the time of treatment. Patients' demographic and laboratory values were also recorded. In total 47 patients underwent CA of 52 HCCs and 46 patients underwent MWA of 66 HCCs. The demographic data was only significant for differences in the alpha-fetoprotein (median 11.3 (IQR:85.5) in CA vs 6.7 (IQR:8.2) MWA, p=0.012) there were no significant differences in the demographic variables. There was no significant difference in the number of incomplete ablations (4/52 7.7% in CA vs 9/66, 13.6% MWA, p=0.38) or local recurrences (11/52, 21.2% CA vs 13/66, 19.7% MWA p=0.98). The median local TTP was not reached but the mean was 49.5 (95%CI: 39.3-59.8) months for CA and 51.2 (95%CI: 43.5-58.9) months MWA. There was no significant difference in local TTP on Kaplan-Meier analysis between the two groups (HR: 0.65 (95%CI: 0.29-1.46), p=0.30. When evaluating overall TTP the median for CA was 16.2 months (95%CI: 5.4-43.9 months) as compared to 16.6 months (95%CI: 12.6-25.7) months for MWA. No significant differences were noted in overall TTP between the two cohorts on Kaplan-Meier analysis (0.99 (95%CI: 0.6-1.64), p=0.98). The median overall survival for the CA cohort was 44.1 (95%CI:19.6-45.4) months as compared to 77.3 (95%CI:29.3-77.3) months in the MWA cohort. When compared by Kaplan-Meier analysis there was no significant difference in overall survival between the two cohorts HR: 0.63 (95%CI:0.33-1.21), p=0.17. No significant differences were noted in terms of incomplete ablation, local TTP, overall TTP, or overall survival in patients with HCC who underwent either CA or MWA.