A prospective study of tumor and technical factors associated with positive margins in breast-conservation therapy for nonpalpable malignancy

BackgroundThe purpose of this study was to identify factors that predict an increased risk of a positive surgical margin after breast-conserving therapy for nonpalpable carcinoma of the breast.MethodsIn this prospective study, 305 patients with nonpalpable invasive breast cancer or ductal carcinoma in situ were identified and underwent localization lumpectomy. Patient, technical, and tumor factors with a potential to predict margin status were documented.ResultsA 20% positive margin rate was observed. Univariate analysis of patient, tumor, and technical factors revealed that localizations performed under stereotactic guidance (P < .001), presence of in situ disease, high tumor grade, larger tumor size, multifocal disease, and presence of mammographic microcalcifications (P < .02) were predictive of positive margins. With the exception of tumor grade and mammographic microcalcifications, multivariable analysis identified the same factors.ConclusionsThis study identified several factors associated with positive margins that should be considered when planning breast-conserving therapy for nonpalpable tumors.