2:34 PM Abstract No. 89 - ■ FEATURED ABSTRACT Midterm results of percutaneous microwave ablation of liver tumors using a 2.4GHz gas - cooled probe: single center evaluation of safety and efficacy

Abstract

Purpose To evaluate the local efficacy, safety, and survival at midterm follow up using percutaneous microwave ablation (MWA)in the treatment of liver tumors. Materials and Methods Over an 18 month period, 64 patients with unresectable liver tumors (18 women, 46 men; mean age 65) underwent 68 percutaneous CT guided MWA procedures using the Certus 140 2.45GHz gas cooled probe (Neuwave Medical, Madison, WI). A retrospective analysis was performed using medical records to review tumor size and location as well as technical and clinical outcomes. Follow-up consisted of a clinic visit and CT or MRI at 1 month and every 3-4 months thereafter. Complete response was defined as disappearance of arterial enhancement. Primary endpoints included: rate of complete ablation, local tumor progression within 1cm from ablated site, and 30 and 90 day major and minor adverse events (AEs). Results A total of 68 tumors were treated (median size 1.9 cm; range 0.7-5.0). Lesion size included: 5cm - 0/68 (0%). Tumor pathology included: 59/68 (86.8%) hepatocellular carcinoma and 9/68 (13.2%) liver metastases. Technical success was 100% using a standard MWA protocol. Repeat intervention was performed in 3/56 (5.4%) patients because of residual enhancement on follow up imaging suggesting viable tumor. Mean time to repeat intervention was 177 days (range, 49-277). All repeat interventions were technically successful. Complete ablation was achieved at 1-,3-,6- and 9-month follow up in 54/56(96.4%), 39/41(95.1%), 21/24 (87.5%), 17/18 (94.5%) patients, respectively. Local tumor progression rates at the ablated site at 1-, 3-,6- and 9-month follow up were 3.6%, 4.9%, 12.5%, and 5.5%, respectively. Mortality was 0% at 30 and 90 days. Length of hospital stay was 1 day in 54/64 (84.3%) patients. Pneumothorax requiring chest tube occurred in 3/68 (4.4%) ablations. Minor AEs included: postprocedural pain and transient low grade fever occurring in 43/64 (67.2%) and 6/64 (9.4%) patients, respectively. Conclusion Percutaneous MWA of hepatic tumors is a safe and locally effective treatment for unresectable hepatic tumors as evidenced by high rates of complete ablations and low rates of major AEs.