Margin width is not predictive of residual disease on re-excision in breast conserving therapy

Background There is lack of consensus regarding re-excision in breast-conserving therapy (BCT) and close margins. We hypothesize that margin width does not predict residual disease. Methods The cancer registry was queried from 2003 to 2008 for patients with BCT who underwent re-excision for Results One thousand eight hundred forty-three patients underwent BCT. Our re-excision rate was 42%. Clinicopathologic factors from 228 patients were analyzed. One hundred five patients (46%) had additional disease; of those, 58% had BCT and 42% mastectomy. One hundred twenty-three (54%) had no additional disease; of those 82% had BCT and 18% mastectomy. Of the 66 patients who underwent mastectomy, 44 (67%) had residual disease; of the 161 who had BCT, 61 (38%) had residual disease (P < 0.01). On univariate analysis, margin width did not correlate with residual disease. Multifocality, non-invasive histology, increasing number of close margins, and higher grade predicted additional disease (P < 0.05). On multivariate analysis, only number of close margins remained significant. Conclusions Margin width does not predict additional disease. This challenges the practice of using this to select re-excision candidates. Our data suggest that tumor behavior and extent of disease, defined by volume of residual disease and invasiveness of histology, play a more significant role. J. Surg. Oncol. 2014 109:426-430. (c) 2013 Wiley Periodicals, Inc.