Purpose: To assess the technical feasibility, patient acceptance, imaging and clinical outcomes of percutaneous US-guided cryotherapy for breast fibroadenomas in patients considered for surgical resection.

Methods and Materials: Forty-two fibroadenomas (FAs) were treated in 27 patients by a 2.4-mm cryoprobe inserted into the FA under US guidance. The first 7 patients underwent conscious sedation but the last 25 patients required only local anesthesia. Ultrasound and thermocouple monitoring of the procedure was performed to evaluate freeze protocols based on tumor size. Saline injections interposed between the developing iceball and the skin or chest wall provided further thermal protection. Ultrasound follow-up scans were done at: 1 week; 1, 3, 6 and 12 months. Pre- and 12 months post-cryotherapy mammograms were available for 7 patients over 30 years old.

Results: Patients reported minimal discomfort when only using local anesthesia. The average pre-treatment FA volume was 4.2 + 4.7 cm3, which reduced to 0.7 + 0.8 cm3 at 12 months (73% reduction, p<0.0001). Ultrasound produced excellent ice visualization beyond tumor margins while thermocouples confirmed cytotoxic temperatures ~3mm behind the US-leading edge. No significant complications were noted and patients were very pleased with cosmetic results and resolution of palpable mass effect by ~6 months. Mammograms showed comparable resolution of mass effects with mild surrounding parenchymal reaction, no dystrophic calcifications, and general preservation of the collagenous architecture

Conclusion: Percutaneous cryotherapy of FAs is a safe, effective, and virtually painless procedure that offers an office or clinic-based treatment option with good cosmesis. Tailored freeze times can be achieved by accurate US visualization of ice >3mm beyond tumor margins. (A grant was received from Sanarus, Inc.)