The principle of tumour ablation, defined as the direct application of chemical or thermal therapies to a tumour to achieve eradication, has been around for more than 100 years. However, advances in interventional radiology and imaging techniques have led to the rise of percutaneous image-guided ablative therapies, which offer significant advantages compared with traditional cancer treatments: reduced morbidity and mortality, lower procedural cost, the ability to perform procedures in an outpatient setting, repeatability, and synergy with other cancer treatments.

Many ablation techniques are used, from more basic methods like ethanol ablation, through laser ablation and cryoablation, to radio-frequency ablation as the most advanced. The last of the modalities to be introduced into therapy 20 years ago was microwave energy in tumour ablation. Nowadays, this method leads the percutaneous ablation narrative with several potential benefits that may increase its effectiveness in the treatment of tumours, including consistently higher intratumoural temperatures, larger ablation volumes, faster ablation times, improved convection profile, optimal heating of cystic masses, and less procedural pain.

However, in Croatia, image-guided percutaneous ablation procedures have largely been underutilised in the past, for various reasons, but mainly due to lack of availability of the new technologies, lower interest in non-vascular procedures among interventional radiologists, and lack of faith in the non-surgical methods.

Microwave ablation (MWA) performed under CT guidance was non-existent in Croatia until 2017, so the purpose of our talk is to show the somewhat difficult road we took to introducing and incorporating percutaneous ablative therapy into oncological algorithms at our institution, to the point where we now have a growing demand for these procedures.

However, even after three years of successful work, we still run into unexpected obstacles and colleagues unconvinced of the efficacy of image-guided ablative therapy.

Percutaneous CT-guided microwave ablation (MWA) of a large Th10 thoracic vertebra metastasis from renal cell carcinoma.

In a retrospective analysis of our first 150 patients treated with percutaneous CT-guided microwave ablation from 2017 to 2019, we analysed the efficacy, complications and patient outcome in different areas where it can be applied. We treated 78 kidney tumours, 42 liver malignancies, nine bone tumours, and 22 lung tumours. We had the opportunity to use different available microwave devices, and all of our procedures were performed with CT guidance, sometimes in combination with ultrasound.

The best results were achieved with kidney cancer ablation, with a recurrence rate of 2.3% after the initial treatment, which was followed up with a second round of MWA. The highest recurrence rate and worst clinical outcome was observed with liver colorectal metastases larger than 3cm and with multiple lesions at initial presentation.

There were two cases of significant complications after MWA in patients with biliary duct thermal injury and stenosis, and colon thermal injury with perforation, which were treated surgically. There was only one case of severe bleeding after ablation, which was treated with embolisation in the angio suite.

Percutaneous CT-guided microwave ablation has a growing role in the therapy of liver, kidney, lung, and bone tumours in Croatia, and with our good results in the first 150 patients since 2017, there is a higher awareness about the role of interventional radiology in cancer treatment.

Luka Novosel is an interventional radiologist at the clinical department of diagnostic and interventional radiology at Sestre Milosrdnice University Hospital in Zagreb, Croatia.

Research Presentation Session
RPS 109 Liver malignancies: HCC and metastases

Introduction and early experience with percutaneous microwave ablation in Croatia: our first 150 cases
L. Novosel; Zagreb/HR

Read the full abstract in the ECR 2020 Book of Abstracts
Novosel L. (2020) Introduction and early experience with percutaneous microwave ablation in Croatia: our first 150 cases. Abstract RPS 109-6 in: ECR 2020 Book of Abstracts. Insights Imaging 11, 34 (2020). DOI 10.1186/s13244-020-00851-0