MRI findings of cancers preoperatively diagnosed as pure DCIS at core needle biopsy

Under-estimation of invasion components occur occasionally at core needle diagnosed ductal carcinoma in situ (DCIS) that may change the prognosis or treatment planning.

To determine whether enhanced magnetic resonance imaging (MRI) features of biopsy-proven ductal cancers in situ help predict the under-estimation of invasive breast cancers.

After a retrospective review of the enhanced MRI features on preoperative proven breast ductal cancers in situ by biopsy, tumor morphology (mass and non-mass), enhancing curve patterns, and non-mass enhanced appearances were compared between pure ductal cancers in situ and invasive ductal cancers (IDCs) after surgery. A statistical analysis was performed, and P values <0.05 were deemed significant.

Twenty-five breast cancers from 24 women were analyzed. Eleven DCIS remained as DCISs, and 14 were upgraded to IDC after surgery. Eight of 14 IDCs (57%) and one of 11 DCISs (9%) presented as mass lesions; otherwise six (43%) IDCs and 10 (91%) DCISs were non-mass lesions (P = 0.013). Among the non-mass cancers, six of 10 DCISs (60%) were focally enhanced and six of 6 IDCs (100%) were segmentally enhanced. The overall cancer sizes measured on enhanced MRI were moderately correlated with histopathology, with a Spearman's rank correlation coefficient of 0.656 (P = 0.001). The mean diameter of the IDCs was larger than that of the pure DCISs on enhanced MRI (2.69 ± 1.42 cm for IDC and 1.62 ± 1.03 cm for DCIS; P = 0.048). The cut-off size was optimally selected at 1.95 cm with a 64% sensitivity and a 77% specificity, using a receiver-operating characteristic curve. The enhancement curves, with washout or persistent rising, were statistically insignificant (P = 0.085 and 0.93, respectively).

Enhanced MRI provided informative morphology and size features that might help to predict the underestimation of invasiveness in preoperative biopsy-proven DCIS.