Microwave Ablation for Treatment of Small Renal Tumors and Primary and Secondary Liver Neoplasms

Purpose The locoregional interventional oncological treatment approach is an accepted modality for liver neoplasms, especially for hepatocellular carcinoma (HCC) and oligonodular liver metastases. Materials and Methods The main aim of ablation therapies like microwave ablation (MWA) is to eradicate all malignant cells in a minimally invasive technique under imaging guidance while preserving the healthy tissue with a sufficient safety margin (at least 5 mm) surrounding the ablated lesion. Results Ablation therapy can be performed via a percutaneous, laparoscopic or intraoperative approach under ultrasound, MRI or CT guidance for adequate localization and monitoring of the ablation process. Conclusion Ablation is the method of choice for oligonodular HCCs ≤ 3 cm. The technical success rate varies from 88 % to 98 % and progression-free survival (PFS) at 3 years from 27 % to 91.7 %. The same criteria apply to the therapy of liver metastases. Key Points Citation Format

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Microwave ablation of 105 T1 renal tumors: technique efficacy with a mean follow-up of two years

Acta Radiologica ◽

10.1177/0284185120956283 ◽

2020 ◽

pp. 028418512095628

Author(s):

Vanessa Acosta Ruiz ◽

Pär Dahlman ◽

Einar Brekkan ◽

Maria Lönnemark ◽

Anders Magnusson

Keyword(s):

Microwave Ablation ◽

Small Sample ◽

Renal Tumors ◽

Efficacy Rate ◽

Primary Efficacy ◽

Curative Intent ◽

Renal Masses ◽

Contrast Enhanced Ct ◽

Potential Benefits

Background Thermal ablation (TA) with radiofrequency (RFA) or cryoablation (CA) are established treatments for small renal masses (≤4 cm). Microwave ablation (MWA) has several potential benefits (decreased ablation time, less susceptibility to heat-sink, higher lesion temperatures than RFA) but is still considered experimental considering the available small-sample studies with short follow-up. Purpose To evaluate technique efficacy and complications of our initial experience of renal tumors treated using percutaneous MWA with a curative intent. Material and Methods A total of 105 renal tumors (in 93 patients) were treated between April 2014 and August 2017. MWA was performed percutaneously with computed tomography (CT) guidance under conscious sedation (n=82) or full anesthesia. Patients were followed with contrast-enhanced CT scans at six months and yearly thereafter for a minimum of five years. The mean follow-up time was 2.1 years. The percentage of tumors completely ablated in a single session (primary efficacy rate) and those successfully treated after repeat ablation (secondary efficacy rate) were recorded. Patient and tumor characteristics as well as complications were collected retrospectively. Results The median patient age was 70 years and median tumor size was 25 mm. Primary efficacy rate was 96.2% (101/105 tumors). After including two residual tumors for a second ablation session, secondary efficacy was 97.1% (102/105). Periprocedural complications were found in 5.2% (5/95) sessions: four Clavien-Dindo I and one Clavien-Dindo IIIa. One postprocedural Clavien-Dindo II complication was found. Conclusion MWA has high efficacy rates and few complications compared to other TA methods at a mean follow-up of two years.

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