Percutaneous pulmonary radiofrequency ablation: difficulty achieving complete ablations in big lung lesions

The size of both primary and metastatic lung tumours often exceeds 3 cm in diameter at the time of diagnosis. The radiofrequency (RF) electrodes of the three leading companies currently in use are designed for a maximum ablation diameter of 5 cm. Therefore, the tumour to be ablated should not exceed 3 cm in maximum diameter, as a I cm safety ablation margin surrounding the tumour should ideally be achieved. A possible solution in treating larger tumours is to create overlapping ablations, a method successfully used in the radiofrequency ablation (RFA) of liver tumours. We report on the percutaneous overlapping ablation of three large lung metastases, 4 cm, 4.5 cm and 5 cm in their longest diameter. The largest of them showed incomplete ablation with residual viable tumour tissue. The overlapping percutaneous RFA of large lung tumours is feasible although the bigger the lesion, the higher the risk of incomplete ablation appears compared with smaller tumours treated by a single ablation.