Role for intraoperative margin assessment in patients undergoing breast-conserving surgery

Positive/close margins are associated with higher in-breast failure rates after breast-conserving surgery (BCS). We investigated whether intraoperative margin assessment aids in obtaining negative margins, and to evaluate the local control thus achieved.

Between 1994 and 1996, 264 patients underwent BCS for stages 0-III breast cancer [invasive, n = 200; ductal carcinoma in situ (DCIS), n = 64]. Intraoperative margin assessment included gross tissue inspection, specimen radiography, with or without frozen section.

Ninety-two patients (46%) with invasive cancer and 24 (38%) with DCIS had positive/close margins on the permanent section analysis of their initial surgical specimens. Fifty-eight patients (29%) with invasive cancer and six (9%) with DCIS had initial positive/close margins, and were rendered margin-negative by intraoperative analysis and immediate re-excision. Final margins on permanent pathology were positive/close in 52 patients (20%): 34 patients (17%) with invasive cancer and 18 patients (28%) with DCIS. By multivariate analysis, excisional biopsy for diagnosis, larger tumor size, and multifocality were associated with final positive/close margins. Of these 52 patients, 23 underwent a second operation to achieve widely negative margins (13 completion mastectomies, 10 re-excisions). The 5-year ipsilateral breast recurrence-free survival rates after BCS and radiation were 99% for invasive cancer (n = 167) and 100% for DCIS (n = 27).

Intraoperative assessment of margins assisted in identifying positive/close margins and allowed over a quarter of the patients to be rendered margin-negative with intraoperative re-excision at their original operation. This approach resulted in excellent local control in patients treated with BCS and radiation.