7P - Current diagnostic strategy for mammographic microcalcification without specific ultrasound abnormality

Abstract

BackgroundStereotactic vacuum-assisted breast biopsy (SVAB) is widely used to evaluate predominantly mammograhic microcalcifications without specific ultrasound abnormalities. Recently however, there raise the problem that screening mammography detect the indolent low grade ductal carcinoma in situ (DCIS), and such diseases don’t necessarily have to be diagnosed by invasive SVAB examination. Moreover, breast magnetic resonance imaging (MRI) has increasingly been performed over the past 10 years and reveals high sensitivity for detecting breast cancer, especially tumor undetectable by ultrasound. The purpose of this study was to assess the optimal indications for SVAB. MethodsFive hundred and eighty-one patients with mammographic microcalcifications underwent SVAB between 2008 and 2014 in our hospital. All calcification lesions were classified into several groups according to the calcification categories (CC) and the presence of suspicions MRI abnormalities. We examined the rate of malignant disease in the subgroups. BI-RADS 4 and 5 MRI lesions were defined as suspicious MRI abnormality (SMA). We considered high grade DCIS and invasive ductal carcinoma (IDC) as worrisome disease ought to be diagnosed. ResultsThe rate of malignancy was 6.3 % in CC2, 14.3% in CC3, 30.3% in CC4, and 80.0% in CC5 altogether. Of 581 patients, two hundred and thirty-three patients were underwent contrast enhanced MRI. Among category 3 or 4 microcalcifications without SMA (134 lesions), results of SVAB revealed 22 malignant lesions (16.4%), including 21 low grade DCIS and only one high grade DCIS and no IDC. If the lesions were accompanied by SMA, the rate of malignancy in these categories was increased to 66.2% (51/77), including 8 high grade DCIS and 14 IDC. If the regions were classified to category 5, about three forth cases were accompanied by SMA (17/23). Half of the category 5 lesions without SMA was malignant (3/6), including one high grade DCIS. ConclusionsMammographic microcalcification classified as 3 or 4 without suspicious MRI abnormal lesion were not be recommended for stereotactic vacuum-assisted biopsies. Legal entity responsible for the studyNaoki Sato. FundingHas not received any funding. DisclosureThe author has declared no conflicts of interest.Table7PTableMRI (-)MRI (-)MRI (-)MRI (+)MRI (+)MRI (+)category 3category 4category 5category 3category 4category 5Benign753331760ADH400120Low grade DCIS138211186High grade DCIS101355IDC000688