Radiofrequency ablation of invasive breast carcinomas:: A phase II trial

Background: Local ablative therapy of breast cancer represents the next frontier in the minimally invasive breast-conservation treatment. We conducted a phase II trial to evaluate radiofrequency ablation (RFA) of invasive breast carcinomas. Methods: Consecutive patients from two Mexican Institutions with invasive breast cancers < 4 cm, with no multicentric tumors and no previous chemotherapy were included in this trial. Under ultrasound guidance, the tumor and a 5 mm margin of surrounding breast tissue were ablated with saline-cooled RFA electrode followed by surgical resection. Routine pathologic analysis and viability evaluation with NADPH-diaphorase stain were performed to assess tumor ablation. Procedure-associated morbidity was recorded. Results: Twenty-five patients were included. Mean patient age was 55.3 years (range 42-89 years). Mean tumor size was 2.08 cm (range 0.9-3.8 cm). Fourteen tumors (56%) were < 2 cm. The mean ablation time was 11 minutes using a mean power of 35 W. During ablation, the tumors become progressively echogenic that corresponded with the region of severe RFA injury at pathologic examination. Of the 25 patients treated, NADPH stain showed no evidence of viable malignant cells in 19 patients (76%), with significant difference between tumors < 2 cm (complete necrosis in 13 of 14 cases, 92.8%) vs. those > 2 cm (complete necrosis 6 of 11 cases, 54.5%) (P < .05). No significant morbidity was recorded. Conclusions: RFA is a promising minimally invasive treatment of small breast carcinomas, as it can achieve effective cell killing with a low complication rate. Further studies are necessary to optimize the technique and evaluate its future role as local therapy for breast cancer.