Theodora Anne Potretzke MD, Presenter: Nothing to Disclose

Timothy J. Ziemlewicz MD, Abstract Co-Author: Nothing to Disclose

J. Louis Hinshaw MD, Abstract Co-Author: Stockholder, NeuWave Medical Inc Medical Advisory Board, NeuWave Medical Inc Stockholder, Cellectar Biosciences, Inc

Meghan G. Lubner MD, Abstract Co-Author: Nothing to Disclose

Douglas Robert Kitchin MD, Abstract Co-Author: Nothing to Disclose

Christopher L. Brace PhD, Abstract Co-Author: Shareholder, NeuWave Medical Inc Consultant, NeuWave Medical Inc

Parul Agarwal, Abstract Co-Author: Nothing to Disclose

Fred T. Lee MD, Abstract Co-Author: Stockholder, NeuWave Medical, Inc Patent holder, NeuWave Medical, Inc Board of Directors, NeuWave Medical, Inc Patent holder, Covidien AG Inventor, Covidien AG Royalties, Covidien AG

To compare the safety and efficacy of radiofrequency (RF) ablation to high-powered gas-cooled microwave (MW) ablation for the treatment of hepatocellular carcinoma (HCC) at a single center.

This IRB-approved retrospective review included 68 tumors in 53 patients treated by RF (12/2001-11/2011) and 135 tumors in 90 patients treated by MW (12/2010-3/2014). Treatments occurred at a single institution and were performed by the same group of operators. Patient demographics, tumor size, rate of local tumor progression (LTP), and procedure-related complications were compared between groups. Complications were recorded according to the Clavien-Dindo classification. Comparisons of proportions between groups were done using a Fischer’s Exact Test with p<0.05 considered statistically significant.

There was no significant difference in patient demographics or size of treated tumors. Mean tumor size was 2.2 cm in the RF group (0.6-4.5) and 2.1 cm in the MW group (0.5-4.2). The majority of treated tumors in both groups were < 3 cm (76.5% in RF group and 86.7% of MW group). Median follow up period was longer for the RF patients (31 months versus 13 months for the MW group). The overall rate of local tumor progression was statistically significantly higher for RF than for MW (17.6% versus 5.9%, p=0.012). The rate of LTP for tumors < 3 cm was greater for RF than MW (13.5 vs. 6% respectively) but this difference was not statistically significant (p=0.13). The rate of LTP for tumors ≥ 3 cm was also greater for RF than MW (31.3 vs. 5.6% respectively), but the difference was not statistically significant due to the small sample size (p=0.08). There were few serious (≥ grade III) complications in either group (2 RF – symptomatic small hemothorax requiring thoracentesis, intraperitoneal bleed requiring exploratory laparotomy; 1 MW – intra-procedural pneumothorax treated with pleural blood patch) (p=0.28).

MW ablation of HCC offers a safe alternative to RF ablation with improved local tumor control at short term follow up.

Microwave ablation has theoretical heating profile advantages over RF ablation and this study demonstrates this may lead to improved local tumor control with treatment of hepatocellular carcinoma.

Potretzke, T, Ziemlewicz, T, Hinshaw, J, Lubner, M, Kitchin, D, Brace, C, Agarwal, P, Lee, F, Microwave versus Radiofrequency Ablation for the Treatment of HCC: A Comparison of Efficacy and Safety at a Single Center.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14018428.html