Radiofrequency Ablation for Early Stage Breast Cancer as a Potential Alternative to Partial Mastectomy: 5-Year Results from the Multiple-Center, Single-Arm, Phase 3 RAFAELO Study (NCCH1409).

[BACKGROUND] At present, no clinical guidelines have been established regarding the use of radiofrequency ablation (RFA) for early stage breast cancer. The Radiofrequency Ablation Therapy for Early Breast Cancer as Local Therapy (RAFAELO) study aimed to assess the efficacy and safety of RFA as an alternative to partial mastectomy in patients with early stage breast cancer.

[PATIENTS AND METHODS] This study was a multicenter, single-arm, phase 3 study. Female patients with a single breast cancer classified as Tis-T1 (tumor size ≤ 1.5 cm), N0M0 Stage 0-I underwent treatment RFA. All patients then received radiation therapy totaling 45-60 Gy. The primary endpoint was the 5-year ipsilateral breast tumor recurrence-free survival (IBTRFS) rate. The threshold for a clinically unacceptable 5-year IBTRFS rate was set at 90% with a one-sided alpha of 5%.

[RESULTS] A total of 370 patients underwent RFA and 353 patients (median [IQR] age, 55 [47-65] years) completed the 5-year follow-up. For the primary endpoint, the IBTRFS rate at 5 years was 98.6% (90% CI 97.1-99.3%, 95% CI 96.6-99.4%). The lower limit of the 90% CI was greater than the threshold of 90%, suggesting the noninferiority of RFA to historical control partial mastectomy. During the study, two recurrences were observed in the ipsilateral breast. Skin ulceration grade ≥ 3 was observed in just one of the 370 patients.

[CONCLUSIONS] RFA was shown to be a safe and minimally invasive treatment for early stage breast cancer, comparable in efficacy to partial mastectomy.