Ultrasound-guided, percutaneous cryotherapy of small (< or = 15 mm) breast cancers.

RATIONALE AND
OBJECTIVE: The purpose of this study was to investigate the feasibility, efficacy, and safety of ultrasound-guided percutaneous cryotherapy of stage T1 breast cancers.
MATERIALS AND METHODS: Thirty patients with biopsy-confirmed breast cancers with tumor diameters of 15 mm or smaller (range, 5-15 mm; median, 12 mm) underwent cryotherapy. After local anesthesia, a 3-mm cryo probe was placed into the tumor under ultrasound guidance. All tumors were subjected to 2 freeze cycles with an interposing thawing cycle. The size of the ice-balls, their distance to the skin, and the temperature at the tip of the probe were closely monitored during the procedure. The patients underwent surgery within 6 weeks and the specimens were evaluated histologically.
RESULTS: The median minimum temperature reached -146 degrees C (range, -117 degrees C to -167 degrees C). In 5 of 29 patients, remnant ductal carcinoma in situ was detectable histologically after cryotherapy beyond the margin of the cryosite in the specimens after open surgery. In 24 patients, no viable tumor cells were found. No severe side effects occurred. In one patient, the cryo procedure was not performed completely because of technical problems. DISCUSSION: Percutaneous cryotherapy is a feasible and safe procedure in minimally invasive therapy for small breast cancers. Residual ductal carcinoma in situ may be attributable to the beginning of a learning curve or by false-negative detection in pre-interventional imaging. Magnetic resonance mammography might aid in treatment planning and for therapy monitoring to better define target tissue and to correlate the tumor margin with the ice-ball.