The effectiveness of microwave ablation in the treatment of liver tumours and correlation of the achieved ablation zone with the manufacturer's expected ablation zone

Abstract

Purpose: Hepatic lesions including hepatocellular carcinoma and metastases are a leading cause of cancer-related deaths worldwide. 1,2 Hepatectomy offers curative potential, however, concurrent cirrhosis and advanced disease stage exclude surgical resection. Microwave ablation (MWA) is a relatively new treatment modality that has become an increasingly utilized alternative and offers advantages such as larger and quicker ablations.3 Recent studies have demonstrated similar survival rates and lower complication rates when comparing MWA to hepatectomy.4,5,6 To our knowledge, this is one of the first studies to examine manufacturer guideline accuracy when predicting ablation zone size. Furthermore, the effectiveness of MWA will be evaluated; including the rates of technical success, complications and local recurrence. Materials and methods: Retrospective study of 11 patients undergoing MWA of hepatic tumours at Nambour General Hospital between 2015-2017 using AMICA probes. The ablation power and duration were determined prior to the procedure based on the required ablation size. Technical success was defined as the absence of tumour enhancement on post-ablation CT, whilst enhancement in the ablation zone on follow-up was considered local recurrence. Ablation zones on post-procedure CT were compared with manufacturer predicted ablation size. Results: Fourteen hepatic lesions were treated by MWA in 11 patients. The majority of patients had cirrhosis (72%) with an average age of 66. Most lesions were located in the right lobe (78%) with a mean diameter of 27 mm (range 13-41 mm). The majority (57%) of procedures were performed under ultrasound guidance with 35% of cases requiring combination with CT. The most commonly utilized probe was the 16 gauge (57%), with an average ablation time of 7 min (3-10 min) and average power of 54 W (20-80 W). Post-ablation imaging demonstrated a technical success rate of 100%. At longest follow-up (4-17 months), only two patients (30%) had disease recurrence with four patients (60%) demonstrating new lesions. The achieved ablation zone was similar to the manufacturer's expected ablation size for examined lesions. Minor complications not requiring intervention occurred in three ablations (21%), including a hematoma and pleural effusion. Post-procedure length of stay was only one day for 76% of patients. There were no procedure-related deaths, with two deaths secondary to disease progression (>12 months post-procedure). Conclusion: Complete tumour ablation was achieved for all patients at post-procedure CT. Our data shows that MWA can safely and effectively achieve local tumour control with minimal complications. Similar ablation zones were demonstrated when comparing actual ablation zones with manufacturer predicted size on the AMICA system.L618976728 <br />