Small (≤2-cm) breast cancer treated with US-guided radiofrequency ablation:: Feasibility study

PURPOSE: To determine the feasibility and safety of ultrasonographically (US) guided percutaneous radiofrequency (RF) ablation in the local treatment of invasive breast carcinomas 2 cm or less in greatest diameter. MATERIALS AND METHODS: RF ablation of 21 malignant lesions was performed in 20 patients immediately before their scheduled lumpectomy or mastectomy. A 15-gauge needle electrode was placed in the lesions, and the prongs of the needle electrode were deployed with real-time US guidance. A temperature of approximately 95 degreesC was maintained for 15 minutes at the tips of the prongs. Histopathologic examination of the resected specimens included use of nicotinamide adenine dinucleotide in its reduced form-diaphorase stain, which is specifically used to confirm thermal cell injury and lack of viability. The desired outcome of the procedure was ablation of the tumor and of an adequate margin around it, as confirmed by the absence of viable tissue in the surgical specimen. RESULTS: In all 21 cases, complete ablation of the target lesion was visualized at US. In one patient, who had undergone preoperative chemotherapy for a mass that was initially judged to be a T2 tumor but who was found to have a small residual tumor at mammography and US performed at the time of ablation, the target lesion was ablated but residual in situ mammographically and US occult invasive carcinoma was found at histopathologic examination. There were no adverse effects. CONCLUSION: US-guided percutaneous ablation of small invasive breast carcinomas is feasible and safe. (C) RSNA, 2004.