Evaluating the relationship between ductal carcinoma in situ, calcifications, and margin status in patients undergoing breast conserving surgery

BACKGROUND: Microcalcifications associated with ductal carcinoma in situ (DCIS-AMC) close to lumpectomy margins could be used as a surrogate for margin involvement and aid in decreasing margin re-excision. We sought to evaluate the histologic factors of DCIS-AMC near lumpectomy margins. METHODS: Women with DCIS treated with breast-conserving surgery (BCS) who had DCIS-AMC on surgical specimens were identified. Pathology slides were reviewed to determine the distance of DCIS-AMC from each margin (six per specimen) and the distance of DCIS from each margin (ie, margin status). RESULTS: Of 35 patients (210 margins), 24 had close/positive margins (39 margins [18%]). DCIS-AMC≤10 mm from a margin was associated with a greater incidence of DCIS≤2 mm from the margin (31.7% DCIS-AMC≤10 mm vs 13.3% no DCIS-AMC≤10 mm, P = 0.003). On multivariable analysis, DCIS≤2 mm from the margin was independently associated with DCIS-AMC≤10 mm from the margin (odds ratio 2.95, 95% confidence interval 1.48-5.86, P = 0.002). CONCLUSIONS: DCIS-AMC≤10 mm from the inked margin is associated with DCIS at or close to the margin (≤2 mm). Using this knowledge, intraoperative techniques like specimen radiography could be utilized to detect microcalcifications≤10 mm from a margin and guide selective margin re-excision in BCS.