Efficacy and safety of percutaneous microwave ablation for liver tumors using an antenna with anti-phase technology offering ultraspherical ablation.

BACKGROUND: Anti-phase technology, a novel advancement in microwave antennas for percutaneous liver ablations, forms more spherical ablation zones. This study aimed to evaluate the efficacy and safety of microwave ablation (MWA) treatment for liver tumors using a microwave antenna equipped with anti-phase technology. PATIENTS AND METHODS: The study included 92 patients (133 lesions) treated with MWA for hepatocellular carcinoma (HCC) or liver metastases. Of these, nine patients had HCC, and 83 had metastases (46 colorectal and 37 non-colorectal metastases). Retrospective analysis was conducted on patients' age, sex, pre- and post-procedural laboratory values (white blood cell count, neutrophil-to-lymphocyte ratio), tumor and ablation zone dimensions (preprocedure and post-procedure day 1 and months 1, 3, and 6), details of the single-shot MWA procedure (duration, power output), procedure-related complications, and local progression/recurrence during follow-up. RESULTS: The technical success rate of MWA was 100%. Ablations were performed at a median power output of 80 watts (range: 50-100), and the mean ablation duration was 5.2 ± 2.1 minutes. Follow-up imaging revealed an ablation zone diameter-to-tumor diameter ratio of 1.63 ± 0.3. Major complications occurred in three patients (3.2%) and included liver abscess (n = 1/92), hemorrhage (n = 1/92), and pleural effusion (n = 1/92). Minor complications were observed in 29 patients (31.5%). The median follow-up time of the patients was 33 (range 10-36) months. The median disease-free survival time was 25 months (95% confidence interval: 21-27). During the 24-month follow-up, local tumor progression occurred in 39 patients (42.4%). Tumor size was identified as an independent risk factor for local progression (p = 0.012). CONCLUSIONS: This study represents the longest follow-up duration and the largest patient cohort for the MWA treatment of liver tumors using anti-phase technology. The results demonstrated high technical success and acceptable local control and complication rates.