Ductal Carcinoma In Situ (DCIS) at Breast MRI: Predictors of Upgrade to Invasive Carcinoma

Rationale and Objectives: To determine the upgrade rate of magnetic resonance imaging (MRI)-detected ductal carcinoma in situ (DCIS) and to identify patient, imaging, and pathologic features that may predict the risk of upgrade. Materials and Methods: Medical chart review from January 2007 to December 2016 identified 60 patients with 61 cases of MRI-detected DCIS and negative mammographic evaluations within 1 year prior to the MRI. Imaging and pathology reports were reviewed. Standard statistical tests, including Student's t-tests and chi-square tests, were used to compare patient, imaging, and pathologic features between the cases of DCIS that did and did not upgrade to invasive carcinoma at surgery. Results: Over a 10-year period, 60 patients (mean age 52 years, range 30-76 years) were diagnosed with 61 cases of MRI-detected DCIS. Two-thirds of DCIS cases were detected on MRI examinations that were performed for purposes of high-risk screening (67.2%, 41/61). MRI features that led to the DCIS diagnosis were nonmass enhancement in 78.7% (48/61), enhancing mass in 16.4% (10/61), nonmass enhancement and enhancing mass in 3.3% (2/61), and enhancing focus in 1.6% (1/61). Thirteen cases (21.3%, 13/61) were upgraded to invasive ductal carcinoma at surgery. DCIS cases that upgraded were larger on MRI (40 mm vs 17 mm, p < 0.01) and more likely to be associated with comedonecrosis at biopsy (38.5% [5/13] vs 6.3% [3/48], p < 0.01). Conclusion: The upgrade rate of MRI-detected DCIS to invasive ductal carcinoma at surgery is 21.3%. Features that are associated with upgrade include large size on MRI and the presence of comedonecrosis at biopsy.