Minimal-Invasive Microwave Coagulation Therapy for Liver Tumours: Laparoscopic and Percutaneous Access

Introduction: Local ablative treatments play an important role in current surgical treatment strategies. Radiofrequency ablation (RFA) as one of the most popular examples suffers from partly inacceptable local tumour control. Microwave coagulation therapy (MCT) is a comparatively new type of ablation promising several improvements. This series is to the best of our knowledge the first within the central European area, which reports on the successful clinical implementation of MCT in a surgical department. Patients and Materials: A novel 915 MHz system (MedWaves (TM), AveCure Inc., SanDiego, CA/U.S.A.) was used to treat 47 patients with 80 tumour nodules in 51 treatment sessions. Average tumour size was 2.6 +/- 0.9 cm. Indications were hepatocellular carcinoma in 29 patients and metastases in 14 as well as 4 cholangiocellular carcinomas. The approach was laparoscopic (20) or percutaneous (31). High-risk conditions defined by unfavourable tumour localisation like invisibility in native transabdominal ultrasound, superficial tumour site or risk of heat sink phenomena were found in 28 cases (53%). Results: Local recurrence rate was 17% on a per-patient and 12% on a per-tumour basis (n = 9). One patient died because of incurable upper gastrointestinal bleeding during the postoperative hospital stay. No MCT-associated complication occurred. Median follow-up period was 20 months. Local tumour recurrence was significantly different on comparing laparoscopic to percutaneous MCT (p = 0.032, chi(2) test), as was global recurrence (p = 0.011, chi(2) test). In a univariate logistic Cox regression, tumour size, access and high-risk localisation were significant prognostic factors for local tumour recurrence, however, in a multivariate reiteration, only the chosen access to MCT (p = 0.012) and tumour size (p = 0.044) remain significant. Conclusion: MCT seems to be a useful tool, easy to implement in a surgical environment and may eventually prove to be superior to other local ablative treatment modalities. Even unfavourable tumour localisations could be treated safely and efficiently using MCT without increased risk of local tumour recurrence.