Mammographic extent of microcalcifications and oestrogen receptor expression affect preoperative breast carcinoma in situ size estimation

Background The aim of our study was to establish which clinical, radiologic and pathologic factors could predict the risk of under- and overestimation of the breast ductal carcinoma in situ (DCIS) size when preoperatively measuring the maximum mammographic extent of microcalcifications (MEM). Methods We made a retrospective review of patients with a DCIS treated in our Breast Unit between May 2005 and May 2012. Clinical, pathologic and radiologic data were evaluated as possible predictive factors for over- or underestimation of DCIS size when measuring MEM. Results We obtained precise measurements of MEM in 82 patients (84 DCIS lesions). Maximum MEM measurement correctly estimated maximum pathology size in 57 lesions (68.7 %). Patients with a correctly estimated DCIS, with an underestimated DCIS and with an overestimated DCIS significantly differed in DCIS ER expression ( p = 0.022) and in maximum MEM measurement ( p = 0.000). Constructing two ROC curves, we found that a maximum MEM measurement ≥25 mm and ER expression ≥90 % were both discrimination points for overestimation and ER ≤ 45 % was a discrimination point for underestimation. Using these cutoff points, we defined four groups of patients with different risks of over- and underestimation. Conclusions Risk of over- or underestimation of DCIS size through MEM measurement depends on DCIS ER expression and MEM itself. Identifying which patients are at a significant risk of over- or underestimation could help the breast surgeon when discussing the surgical options with the patient.