Role of preoperative breast MRI in ductal carcinoma in situ for prediction of the presence and assessment of the extent of occult invasive component.

Ductal carcinoma in situ (DCIS) is a common neoplasm that may be associated with focal invasive breast cancer lesions. The aim of our study was to evaluate the role of preoperative magnetic resonance imaging (MRI) in determining occult invasive presence and disease extent in patients with preoperative diagnosis of pure DCIS. We analyzed 125 patients with postoperative pure DCIS (n = 91) and DCIS plus invasive component (n = 34). Diagnostic mammography (MRX) showed a size underestimation rate of 30.4% while MRI showed an overestimation rate of 28.6%. Comparing the mean absolute error between preoperative MRI and MRX evaluations and final disease extent, MRI showed an improved accuracy of 51.2%. In our analysis preoperative breast MRI showed a better accuracy in predicting postoperative pathologic extent of disease, adding strength to the growing evidences that preoperative MRI can lead to a more appropriate management of DCIS patients.