Significance of Microcalcifications on Mammography in the Surgical Treatment of Breast Cancer Patients with a Preoperative Diagnosis of Ductal Carcinoma in Situ by Core Needle Biopsy

To clarify the surgical outcomes of breast cancer patients with a preoperative diagnosis of ductal carcinoma in situ (DCIS) by core needle biopsy (CNB) (abbreviated as CNBDCIS), we retrospectively analyzed the cases of 131 patients with CNBDCIS who underwent surgery at Oomoto Hospital (32 total mastectomies, 99 conservative mastectomies). Our analysis of underestimation and predictors of invasive breast cancer of CNBDCIS revealed that the underestimation rate of CNBDCIS was 40.5% (53/131). A logistic regression analysis revealed that palpable tumors (yes to no, odds ratio [OR] 3.25), mammography (MMG) category group (category 4 or 5 to categories 1 , 2, or 3, OR 4.69) and MMG microcalcifications (no to yes, OR 0.24) were significant predictive factors for CNBDCIS invasion. In our analysis of the predictors of positive margins during CNBDCIS surgery, 36 (27.5%) of the 131 patients had positive margins after postoperative pathological examination. A logistic regression analysis revealed that the operative procedure (conservative surgery to total mastectomy, OR 21.4) and MMG microcalcifications (yes to no, OR 3.35) were significant factors related to positive margins during CNBDCIS surgery. Thus, MMG microcalcifications are a negative predictor of upgrading of CNBDCIS and a positive predictor of positive surgical margins for CNBDCIS.