Long-term results of phase II ablation after breast lumpectomy added to extend intraoperative margins (ABLATE l) trial.

Abstract

Excision followed by radiofrequency ablation (eRFA) is an intraoperative method that uses intracavitary hyperthermia to create an additional tumor-free zone around the lumpectomy cavity in breast cancer patients. We hypothesized that eRFA after lumpectomy for invasive breast cancer could reduce the need for re-excision for close margins as well as potentially maintain local control without the need for radiation. This prospective phase II institutional review board-approved study was conducted from March 2004 to April 2010. A standard lumpectomy was performed, then the RFA probe was deployed 1 cm circumferentially into the walls of the lumpectomy cavity and maintained at 100 °C for 15 minutes. Validated Doppler sonography was used to intraoperatively determine adequacy of ablation. One hundred patients were accrued to the trial, with an average age of 65.02 years ± 10.0 years. The stages were Tis (n = 30); T1mic (n = 1); T1a (n = 9); T1b (n = 27); T1c (n = 22); T2 (n = 10) ; and T3 (n = 1). Grades were I (n = 48); II (n = 29); and III (n = 23). Seventy-eight subjects had margins >2 mm (negative), 22 patients had margins ≤ 2 mm, of which 12 were close and 3 focally positive, which, at our institution, would have required re-excision (only 1 patient in this group had re-excision). There were 6% postoperative complications, and 24 patients received radiation therapy (XRT). During the study mean follow-up period of 62 months ± 24 months (68-month median follow-up) in patients not treated with XRT, there were 2 in-site tumor recurrences treated with aromitase inhibitor, 3 biopsy entrance site recurrences treated with excision and XRT to conserve the breast, and 2 recurrences elsewhere and 1 contralateral recurrence; all 3 treated with mastectomy. Long-term follow-up suggests that eRFA may reduce the need for re-excision for close or focally positive margins in breast cancer patients, and eRFA may be a valuable tool for treating favorable patients who desire lumpectomy and either cannot or do not want radiation. A multicenter trial has been initiated based on these results.