Surgery for breast cancer has recently become less invasive.The first stage was reducing the amount of resected breast from mastectomy to partial resection.Second, was the shift from conventional axillary lymph node dissection to the sentinel node biopsy in patients without metastasis in the axilla?The third change toward less invasive surgery to achieve local control in breast cancer is the development of non-surgical therapy, for example variants of thermo ablation.Various imaging methods, such as screening mammography can detect small breast cancer.Median size for diagnosed primary breast cancer tumours in Sweden today is 1, 7 cm.Consequently many tumours are suitable for minimally invasive procedures.The technique we developed is called Preferential Radio Frequency Ablation (PRFA).Preferential refers to the observation that tumor tissue is coagulated while surrounding benign tissue is spared.The accessory Fourier hand-piece increases precision when it comes to placing the therapy electrode central in a tumour and without too high pre-strain.Penetration of the tumour can be monitored with ultrasound under ideal conditions.As the first step when introduced in the clinic, we published a feasibility pilot study performing PRFA under general anaesthesia followed by surgical excision.As the next step we can present results where PRFA is used preoperatively, in local anaesthesia, in a separate session evaluated with MRI.Finally we report a series of PRFA treatments as the only method to achieve local control in primary breast cancer.The accessory Fourier technique has now also been implemented in the procedures.