Predictors of positive margins after local excision of ductal carcinoma in situ

Background: This study aimed to examine the association between clinicopathologic parameters and positive margins in women with ductal carcinoma in situ (DCIS) treated by breast-conserving surgery (BCS). Methods: We retrospectively reviewed the clinical, radiologic, and pathologic data of 100 women who had undergone BCS for DCIS in our center. Results: Sixty-seven percent of patients presented via breast screening and 55% of all cases were diagnosed preoperatively on fine needle aspiration cytology ([FNAC] ie, C5). Overall, 45% of patients had clear margins after initial local excision. Positive margins showed a nonsignificant trend of association with distribution of microcalcifications (MCC), nonconsultant operating surgeon, inconclusive preoperative FNAC, presence of necrosis, and low specimen weight. There was a highly significant association between low grade DCIS (P = 0.003) and incomplete excision. There was no significant association with age, associated invasive focus, morphology of MCC, or with mode of presentation. Conclusion: Positive margins after local excision of DCIS are significantly associated with low nuclear grade, and preoperative determination of nuclear grade by core biopsy may have surgical implications. (C) 2001 Excerpta Medica, Inc. All rights reserved.