RÉSUMÉ
PURPOSE: The aim of this study was to estimate the upstaging rate of ductal carcinoma in situ (DCIS) diagnosed by core needle biopsy (CNB) under imaging guidance and to identify factors related to upstaging. MATERIALS AND METHODS: During an 8-year period, pure DCIS was diagnosed by imaging-guided CNB followed by definitive surgery in 128 patients. Data on pathological, clinical, and radiological findings were obtained. RESULTS: DCIS upstaging in the present study was 24% (31 of 128 patients had invasive cancer in the final surgical specimen), and the rate was 41% if the cases with microinvasion were included. Factors significantly associated with any type of upstaging included radiological factors (BI-RADS category), factors related to CNB technique (modality of image guidance, size of the core needle, number of cores), and pathological factors (histological grading and presence of comedonecrosis). Multivariable analysis revealed that higher histological grade [odds ratio (OR) and 95% confidence interval (CI) were 2.50 (1.10-5.67)], smaller needle size (no. 14 vs. no. 11) [OR 3.57 (1.11-11.4)], and the presence of comedonecrosis [OR 3.78 (1.32-10.8)] were significantly and independently related to upstaging. CONCLUSION: High-grade DCIS, using a smaller needle, and the presence of comedonecrosis in the CNB specimen were associated with a higher risk for invasive carcinoma.