[NONSURGICAL ABLATION THERAPY FOR SMALL BREAST CARCINOMAS].

Breast-conserving therapy was introduced in Japan in the 1980s as a local treatment for early-stage disease used under cautiously developed criteria. Its indications have gradually been expanded by, for example, the addition of concomitant preoperative chemotherapy. More than half of breast cancer patients currently benefit from this treatment. Recently, nonsurgical ablative therapies have been tested as a definitive conservative treatment. Clinical studies on high-intensity focused ultrasound (HIFU) and cryoablation began in 2004 and 2006, respectively. Phase I and phase II multicenter clinical trials of radiofrequency ablation (RFA) as a treatment for early-stage breast cancer were started in 2006 under the Evaluation System of Investigational Medical Care. A prospective phase III trial was started in 2013 under the Advanced Medical Service System. Data on nonsurgical ablative therapies including RFA, cryoablation, and HIFU are steadily accumulating. We believe that these therapies can replace lumpectomy, the current standard treatment for early breast cancer, in the near future.