Indications for stereotactically-guided vacuum-assisted breast biopsy for patients with category 3 microcalcifications.

BACKGROUND: Since microcalcifications classified as category 3 on mammography include not only malignant lesions but also benign lesions, it is difficult to decide whether stereotactic vacuum-assisted breast biopsy (Mammotome(R), MMT) should be performed or the patient should merely be follows. The purpose of this study is to adequately diagnose microcalcifications classified as category 3 and to formulate a correct clinical policy. In addition, we examined the characteristics of the calcifications. METHODS: This study included 51 patients who underwent MMT from July 2003 to October 2004. All the cases were evaluated as category 3, and no abnormal findings were detected on ultrasonography. We classified the pattern of calcifications based on three aspects: 1. density and size, 2. pleomorphic appearance 3. number of calcifications per square centimeter. RESULTS: Of the 51 patients, 14 were histologically diagnosed with ductal carcinoma in situ (DCIS). Heterogeneity in the density and size were observed in 9 of 14 patients (64.3%). The calcifications had a pleomorphic appearance in 6 of 14 patients (42.9%). A large number of calcifications (20/cm(2)) were observed in 8 of 14 patients (57.1%). Better examination characteristics were obtained with heterogeneity in density and size (AUC=0.72 95%C.I: 0.56-0.89) compared with pleomorphic appearance and the number of calcifications per square centimeter. The potential for malignancy was an average of 6 times higher for calcifications with heterogeneity in density and size compared to that for calcifications which were homogeneous in these aspects. CONCLUSION: Attention should be paid to prevent unnecessary mammotome procedures. Heterogeneity in the density and size of calcifications is a reliable criterion for clinical decision-making.