Percutaneous microwave ablation of adrenal tumours under ultrasound guidance in 33 patients with 35 tumours: A single-centre experience

Purpose: The aim of this study was to investigate the efficacy and safety of percutaneous microwave ablation (MWA) of adrenal tumours under ultrasound (US) guidance.Materials and methods: A total of 33 consecutive patients with 35 tumours were enrolled. The term technical success' is used to indicate whether the tumour was treated according to protocol and was covered completely by the ablation zone. Technical success, local tumour progression (LTP) and complications were recorded. For seven patients with eight biochemically active tumours, biochemical markers were recorded prior to and after the ablation procedure.Results: In this study, technical success was achieved in all cases. Follow-up imaging was performed on 31 patients with 33 tumours (excluding two patients who were lost to follow-up). LTP occurred for five tumours (15.2%) at a mean of 24 months of follow-up (range 3-82 months). In the subgroup analysis of tumour size and LTP, a significant difference was noted between tumours with a diameter 5cm compared with those >5cm (p<0.01). For seven cases of metabolically active adrenal tumours, technical success was confirmed in all patients, and LTP occurred in one case of recurrent pheochromocytoma. All patients demonstrated the normalisation of abnormal biochemical markers after ablation. No major complications were observed.Conclusion: Percutaneous MWA under US guidance is effective in terms of good local control of adrenal tumours with a diameter of less than or equal to 5cm and is capable of treating biochemically active tumours harbouring clinical syndromes.