Abstract: Objective: To observe the feasibility and safety of cryoablation of unifocal tumor for nonsurgical candidates.Methods: The procedure was performed after achievement of local anesthesia for 15 tumors in 15 patients（13 male and 2 female patients）.Results: The cryoprobe was successfully placed under ultrasound guidance in the tumor in 15（100%） of 15 patients.15 had two freeze cycles consisting of a 15-or 20-minute freeze and a 2-minute thaw.Tumors of 13 patients were thoroughly covered by ice balls.The mean greatest dimension of breast cancer was 8 cm,and 90% of area was covered by ice balls.Median Time-to-progression is eight months.Conclusion: Percutaneous cryoablation therapy for unifocal tumor under ultrasonic guidance is feasible and minimally invasive,with satisfactory local control.Tumor magnitude and location were dependent determinants of ice ball coverage.