Radiopathological features predictive of involved margins in ductal carcinoma in situ

Abstract

INTRODUCTION Ductal carcinoma in situ (DCIS) usually manifests as microcalcification on mammography but may be uncalcified. Consequently, a quarter of patients undergoing excision of a presumed pure DCIS require further surgery to re-excise margins. Patients at highest risk of margin involvement may benefit from additional preoperative assessment. METHODS A retrospective review was carried out of patients treated for screen detected, biopsy proven DCIS in a single centre over a ten-year period (1999-2009). Logistic regression analysis identified factors predictive of need for further surgery to clear margins. RESULTS Overall, 248 patients underwent surgery for DCIS (low/intermediate grade: 82, high grade: 155) and 49 (19.8%) required further surgery. High grade disease was associated with greater mammographic extent (mean: 32mm [range: 5-120mm] vs 25mm [range: 2-100mm]), p=0.009) and higher incidence of mastectomy (38% vs 24%, p=0.034). Factors predictive of involvement of surgical margins necessitating further surgery included negative oestrogen receptor status (OR: 5.2, 95% CI: 2.1-12.8, p<0.001) and mammographic extent (odds ratio [OR]: 1.6, 95% confidence interval [CI]: 1.2-2.1, p=0.004). Once size exceeded 30mm, more than 50% of patients required secondary breast surgery for margins. CONCLUSIONS Reoperation rates for DCIS increase with preoperative size on mammography and negative oestrogen receptor status on core biopsy. Patients with these risk features should be counselled accordingly and consideration should be given to the role of additional preoperative imaging.

Reoperation rate of ductal carcinoma in situ: impact of tomosynthesis (3D) and spot magnification

“…The larger the size of microcalcifications in DCIS, the worse the preoperative imaging is in predicting its true extent. This is in concordance with earlier studies (27,28).…”

“…We evaluated only pure DCIS in needle biopsy cases, which were represented on mammograms as clusters of microcalcifications. The study population was over 150, which is comparable to previously published studies (27,28).…”

“…The present study suggests that additional imaging (spot magnification or tomosynthesis) does not improve the preoperative assessment of biopsy-proven pure DCIS regarding the extent of disease and thus does not reduce the need for additional surgery due to inadequate surgical margins. Early studies (26)(27)(28)(29)(30) have investigated radiopathological features of DCIS, predictive of involved margins; these include concordance of radiological and histological size, DCIS histological grade, type of calcifications, and DCIS estrogen receptor status. Some studies (26,27,31) also evaluated the accuracy of mammography in predicting DCIS histological extent.…”

Indications and methods of intraoperative specimen radiography in breast-conserving surgery

“…In particular, the size of the DCIS tends to be underestimated on radiological imaging based on the range of microcalcifications on mammography, leading to a positive margin (14)(15)(16)(17). Radiopathological discrepancies may exist; however, Layfield et al have reported a statistically significant increase in re-operation rates when the range of microcalcifications exceeded 30 mm (18). Therefore, in cases with a wide range of microcalcifications, it is advisable to use alternative margin assessment methods.…”