Prospective Phase II Multicenter Trial of Ablation after Breast Lumpectomy Added To Extend (ABLATE) Intraoperative Margins for the Sole Local Treatment of Breast Cancer.

BACKGROUND: Excision followed by radiofrequency ablation (eRFA) is an intraoperative method that utilizes intracavitary hyperthermia to create an additional tumor-free zone around the lumpectomy cavity in patients with breast cancer, similar to partial breast irradiation. We hypothesized that intraoperative eRFA extends the "final" tumor-free margin, decreases local recurrence, and maintains cosmesis without the need for radiation (XRT).

PATIENTS AND METHODS: Patients with unifocal ER+PR+HER2- or DCIS tumors less than or equal to 3 cm with clinically negative nodes were included. After standard lumpectomy, the RFA probe was deployed 1 cm circumferentially into the walls of the lumpectomy cavity. RFA was performed at 100°C for 15 min, followed by validated intraoperative Doppler sonography. Pain and cosmesis were assessed with the Radiation Therapy Oncology Group (RTOG) scales.

RESULTS: A total of 242 subjects were accrued to the study, with a median follow-up of 44 months (range 12-96 months); 60% were invasive ductal cancer (IDC), and 33% were ductal carcinoma in situ (DCIS). The average size was 1.1 ± 0.6 cm (0.2-3 cm). Reexcision for positive margins was < 5%. In-breast recurrence rate was 2.9%. Breast pain at 6 months was 19% with RFA combined with XRT versus 1.7% with RFA alone (p < 0.05). Cosmesis was good or excellent in 89% of subjects.

CONCLUSIONS: A majority of the subjects avoided whole breast XRT and mastectomy. Results indicate that eRFA, in lieu of XRT, is safe and effective, resulting in ~fivefold lower pain. By completing therapy in the operating room, eRFA can potentially enhance patient access and compliance, alleviate financial stress, and deliver superior cosmetic and quality-of-life outcomes.