Radiofrequency ablation without excision for breast cancer: 5-year results of ipsilateral breast tumor recurrence-free survival in the RAFAELO study (NCCH1409).

Abstract

578 Background: The RAFAELO study is designed to evaluate the safety and efficacy of breast radiofrequency ablation, enabling women between 20 and 79 years of age with small breast cancers to benefit from a nonsurgical treatment and to avoid the associated surgical risks. Methods: The RAFAELO study is a prospective, multi-center, single-arm, confirmatory trial including women between 20 and 79 years of age with unifocal, MRI and ultrasound-visible invasive ductal carcinoma or ductal carcinoma in situ size 1.5 cm or smaller diagnosed by preoperative core-needle biopsy, and classified as any grade, any hormone receptor (HR) status, and any human epidermal growth factor receptor 2 (HER2) status. The primary endpoint was Ipsilateral breast tumor recurrence (IBTR) -free survival at 5 years. e planned sample size was set at 372 considering patients lost to follow-up to achieve the power of 80% with the one-sided alpha of 5%, the expected 5-year IBTR-free survival of 93.7%, and the threshold of 90%. The IBTR-free survival time was estimated using the Kaplan-Meier method. Results: Between August 2013 and November 2017, 372 patients were enrolled in this study. A total of 370 patients received successful radiofrequency ablation per protocol and 353 patients were included for the efficacy analysis. The median age was 55 years (range, 32-78 years). With median follow-up period of 5 years, IBTR was observed in 2 patients among 353 patients. The 5-year IBTR-free survival was 98.6% (90% CI 97.1%-99.3%) and the primary endpoint was met as its lower limit of 90% CI exceeded the threshold (90%). As device-related adverse events during radiofrequency ablation, burns were observed in 4 (1.1%) for Grade 1 and 3 (0.8%) for Grade 2 among 370 patients. No severe device-related adverse events were reported. Conclusions: Breast radiofrequency ablation presents a promising alternative to surgery while offering the benefits of a minimally invasive procedure with minimal risks. Breast cancer patients in Japan can now avail themselves of this minimally invasive treatment that’s subsidized by public insurance. Further analysis within this clinical trial or registry is needed to confirm radiofrequency ablation as a viable alternative to surgical excision for breast cancer patients in the point of cosmetic results and patient’s satisfaction. Clinical trial information: jRCTs032180229 .