G. MANENTI¹, E. COSSU¹, C.A. PISTOLESE¹, G. Simonetti²; ¹Roma/IT, ²Rome/IT

Purpose
To evaluate the uniformity and reproducibility of thermal lesion ablation on selected breast tumours ≤ 2 cm (mean 1.4 ± 0.5 cm) and quantify the volume of tissue destruction induced with a new commercially available radiofrequency (RF) ablation device and RF-generator.

Material and methods
A new cooled-tip electrode was realized to induce wide thermal lesions in eight swine breasts in vivo and in 12 resected pre and post-menopausal mammary glands from human surgical mastectomy. Five patients with biopsy proven non-palpable invasive breast carcinomas underwent sonographically guided RFTA of their breast tumours under local anesthesia followed by a 12-24 hours delayed resection. Each Patient underwent 3T breast MRI before tumor surgical resection. Histopatological analysis after Hematoxylin-Eosin and nicotinamide-adenine-dinucleotide-diaphorase stainings was performed to verify the completeness of tumour coagulative necrosis and the marginal clearance. Skin or thoracic wall damage and patient reports of pain and procedural acceptability were also recorded.

Results
In resected mammary glands the mean diameter of the radiofrequency–induced lesion was 3.7 ± 0.4 cm corresponding to approximate volume of 26.67 ± 9.59 cm3. In vivo, the mean diameter was 3 ± 0.4 cm corresponding to an approximate volume of 11.16 ± 3.65 cm3. Histopathological examination revealed in all cases the complete coagulative necrosis of the tumor tissue and the typical signs of complete or coagulation necrosis along the free margins of the thermoablated areas. The procedure was well tolerated form patients, without skin or thoracic wall damages.

Conclusion
US-guided percutaneous ablation of small selected invasive breast carcinoma with dedicated device is a feasible and reliable technique because of the higher energy deposition due to the cooling of the needle electrode and to ensure resection of lesion.