Positive margins of breast biopsy: Is reexcision always necessary?

Background and Objectives: Breast-conserving surgery requires excision of a ll gross tumor and subsequent radiation therapy. It is generally accepted t hat the presence of microscopically positive margins requires reexcision. T he goal of this study was to identify characteristics that distinguish brea st biopsy specimens with positive margins that when reexcised are free from residual tumor. This population of patients may benefit from breast irradi ation only, without the need for another surgical procedure. Methods: One hundred and fifteen of 395 cancer-proven biopsies had positive surgical margins and were treated with reexcision or mastectomy. Sixty-sev en of these were negative for residual tumor and 48 were positive for resid ual tumor. Evaluation for tumor type, tumor size, grade, presence of vascul ar invasion, volume of the biopsy specimen, true positivity and the number of positive margins, multifocality of the tumor, and type of anesthesia was done by univariate and multivariate analysis. Results: Univariate and multivariate analysis revealed that factors associa ted with a positive reexcision included margin status, method of detection, histologic appearance, and type of anesthesia used. Conclusion: These results suggest that small, clinically detectable unifoca l tumors could be treated without the need for a further excision. Eradicat ion of microscopic residual tumor could be done by irradiation only, sparin g the patient an additional surgical procedure. J. Surg. Oncol. 1999;70:167 -171. (C) 1999 Wiley-Liss, Inc.