Radiofrequency Ablation in Breast Cancer.

Abstract

Abstract Background: Radiofrequency ablation (RFA) of breast tumors is characterized by variable efficiency. Cell viability is principally evaluated by NADH-diaphorase and Hematoxylin-eosin (H&E) staining techniques.Methods: Twenty patients with breast cancer, 20.7 ± 9.14mm in diameter, underwent RFA of the tumor and of the margin of surrounding breast tissue. RFA was based on the radiofrequency impedance-switching algorithm. The algorithm was based on an internally cooled probe, which carried out algorithm-guided deposition of heat in a pulse-cycle fashion and under continuous monitoring of the desiccation status of the ablated site to avoid tissue charring (until its impedance level reached 30Ω above the baseline level or a maximum time interval (tmax) was reached). A minimum time interval of 5 seconds was set as the duration of time that the electrode must be off. If the cycles of power application occurred too rapidly, the power was diverted to the 150Ω resistance load for the remainder of the 5-second interval. Surgical resection was the next step. Sixteen patients underwent quardzantectomy (five with axillary lymph node dissection) and four unilateral total mastectomy. In fifteen patients SLNB was searched and identified (ten negative, four positive and one failure). The ablated tumor tissue was histologically examined and Ki67 immunohistological staining was applied to evaluate cellular proliferation, invasion and survival.Results: The mean time of operation was 119.47 ± 23.35minutes.The mean time of RFA was 12 - 15minutes. One patient had a post-operative complication (trauma infection). All twenty patients had a positive Ki67 immunohistochemical staining mean value of 28.79 ± 21.42, before RFA. The post-RFA Ki67 expression was zero in sixteen patients. In three patients no residual tumor cells were found and in one patient the Ki67 expression was under five percent. Recurrence developed in zero patients, to date (follow up time: 22.5 ± 2.3 months).Conclusion: Ki67 evaluation is a targeting indicator of viability of malignant cells after lesion RFA of breast tumors. RFA is able to provide satisfactory local control in breast cancer. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2106.