Radiofrequency ablation for early-stage breast cancer: results from 5 years of follow-up in a prospective multicenter study.

Abstract

e12098 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 1 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. Building on these results, we designed a Phase 2 clinical trial to investigate the efficacy of a non-surgical RFA procedure. Methods: From Nov. 2009 to Nov. 2012, 58 patients with early-stage breast cancer received non-surgical RFA therapy. Patients had localized solitary N0 tumors with a maximum diameter of 1 cm. They underwent RFA and sentinel lymph node biopsy under general anesthesia and adjuvant therapy and breast irradiation. Follow-up evaluation for residual tumor at 3, 6, and 12 months after RFA included clinical breast examination, diagnostic imagings (ultrasound, magnetic resonance, and mammography), and vacuum-assisted biopsy. Surgical resection was recommended for patients with suspected residual disease or incomplete ablation. The primary endpoint was the frequency of adverse events. Secondary endpoints included the complete ablation rate and ipsilateral breast relapse-free rate. The diagnostic performance of the follow-up examinations and cosmetic outcomes were evaluated for exploratory purposes. Results: The follow-up period ranged from 450 to 2552 days (median, 1832 days). The 57 patients completed the non-surgical RFA procedure and underwent diagnostic imaging and needle biopsy after 3 months. Seven patients with suspected incomplete ablation underwent surgical resection; incomplete ablation was confirmed in 5 (8.6%, 2 with invasive and 3 with non-invasive ductal carcinoma). During subsequent follow-up, 1 patient each was diagnosed with contralateral breast cancer and brain tumor. No ipsilateral breast tumor relapse or distant recurrence was documented. Cosmetic results were excellent in 94% of patients. Conclusions: RFA is a promising alternative to surgery for treating localized, early-stage breast cancers. Clinical trial information: UMIN000008675.