Simplifying Breast Imaging Reporting and Data System classification of mammograms with pure suspicious calcifications

Objectives To investigate the risk of malignancy following stereotactic breast biopsy of calcifications classified as Breast Imaging Reporting and Data System (BI-RADS) 3, 4, and 5. Methods The study included women with pure calcifications (not associated with masses or architectural distortions) who underwent stereotactic breast biopsy at the Dutch Cancer Institute between January 2011 and October 2013. Suspicious calcifications (Breast Imaging Reporting and Data System 3, 4, or 5) detected on mammography were biopsied. All lesions were assessed by breast radiologists and classified according to the BI-RADS lexicon. Results Overall, 473 patients underwent 497 stereotactic breast biopsies. Sixty-six percent (326/497) of calcifications were classified B4, 30% (148/497) B3, and 4% (23/497) B5. Of the 226 (45%) malignant lesions, there were 182 pure ductal carcinoma in situ, 22 mixed ductal carcinoma in situ and invasive carcinomas (ductal or lobular), 21 pure invasive carcinomas, and one angiosarcoma. Malignancy was found in 32% (95% confidence interval [CI] 0.24 to 0.39) of B3, 49% (95% CI 0.43 to 0.54) of B4, and 83% (95% CI 0.61 to 0.95) of B5 calcifications. Conclusions Considering the high predictive value for malignancy in B3 calcifications, we propose that these lesions should be classified as suspicious (B4), especially in a screening setting.