Multicenter study to evaluate the efficacy and standardize radiofrequency ablation therapy for early breast cancer (RAFAELO study)

Background: Given the increasing number of early-stage breast cancers detected by screening mammography, we aim to establish RFA as a minimally invasive, cost-efficient, and cosmetically acceptable local treatment. In our Phase I study, localized tumors with a maximum diameter of 2 cm, preoperatively diagnosed by imaging and histopathology, were treated with RFA. A 90% complete ablation rate was confirmed histopathologically. Trial design: The objective of our study is to demonstrate the non-inferiority of RFA compared with standard treatment in terms of local recurrence-free survival, which is the best index of local control. The inclusion criteria are untreated pts with histologically confirmed ductal carcinoma with a single localized tumor of 1.5 cm or less in the greatest dimension on preoperative imaging, no prior treatment for breast cancer. RFA is defined as a procedure in which a radiofrequency electrode needle is inserted into the breast lesion from the surface of the body under imaging guidance and thermal ablation with radiofrequency waves is performed. The Cool-tip™ RF Ablation Single Electrode Kit (Medtronic, Boulder, CO, USA) is recommended to standardize the evaluation of the effect of ablation. All pts receive RT and systemic therapy according to the ER, HER2, tumor grade and lymph node status of the primary breast cancer after RFA. Residual lesions after RFA will be assessed in all patients approximately 3 months after RT using imaging studies and pathological examination. VAB will be performed in all patients regardless of imaging results. If biopsy specimens reveals suspicious of viable tumor, additional excision will be performed. Follow-up evaluation for residual tumor every 12 months after RFA included clinical breast examination, diagnostic imagings (ultrasound, magnetic resonance, and mammography). The primary endpoint is 5-year local recurrence-free survival, and the secondary endpoints are residual lesion rate after treatment, overall survival, distant recurrence-free survival and adverse events of RFA. The pts accrual was started in August 2013. From 9 participating institutions, enrollment of 372 pts is planned over a 5-year accrual period. Clinical trial identification: UMIN-CTR: UMIN000005586. Legal entity responsible for the study: Takayuki Kinoshita. Funding: The Japan Agency for Medical Research and Development. Disclosure: All authors have declared no conflicts of interest.