Impact of intraoperative specimen mammography on margins in breast-conserving surgery.

A positive resection margin is one of the most significant risk factors for local breast cancer recurrence following breast-conserving surgery (BCS). Intraoperative specimen mammography (SMMG) is routinely used to evaluate the surgical margin at our institution. The aim of the present study was to assess the adequacy of SMMG for margin assessment. The patient cohort included 174 women who underwent BCS in 2006. The sensitivity and specificity of SMMG were assessed by comparing the margins assessed by histological and radiological methods. It was also examined whether the rate of positive histological margins was decreased by re-excision following SMMG evaluation. A total of 23 false-negatives and 6 false-positives were determined by SMMG. The sensitivity and specificity of SMMG margin assessment for patients with primary breast cancer were 20.6 and 94.6%, respectively. The positive predictive value was 50% and the negative predictive value was 82.2%. A subgroup analysis revealed that the sensitivity and specificity of SMMG in cases with ductal carcinoma in situ (DCIS) were higher compared with those in invasive ductal carcinoma. Furthermore, the positive histological margin rate was not affected by re-excision. Although the general usefulness of intraoperative SMMG was not proven, this procedure may be useful in specific cases, particularly those with DCIS and those diagnosed by stereotactic biopsy. A prospective study with exact criteria and a standard procedure is required.