Underestimation Rate at MR Imaging-guided Vacuum-assisted Breast Biopsy: A Multi-Institutional Retrospective Study of 1509 Breast Biopsies.

Purpose To assess the rate of underestimation of atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) at magnetic resonance (MR) imaging-guided vacuum-assisted breast biopsy and to explore the imaging, demographic, and histologic characteristics associated with lesion upgrade after surgery. Materials and Methods This retrospective study had institutional review board approval, and the need to obtain informed patient consent was waived. A total of 1509 MR imaging-guided vacuum-assisted biopsy procedures were performed in nine centers. A diagnosis of ADH was obtained after biopsy in 72 cases, and a diagnosis of DCIS was obtained in 118 cases. Pearson χ and Fisher tests were used to assess the association between demographic, MR imaging, and biopsy features and lesion upgrade. Univariate statistical analyses were performed, and each significant parameter was entered into a multivariate logistic regression analysis. Results Surgical excision was performed in 66 of the 72 ADH cases and in 117 of 118 DCIS cases. The ADH and DCIS underestimation rates were 25.8% (17 of 66) and 23.1% (27 of 117), respectively. Underestimation was 5.6-fold (odds ratio [OR] = 5.6; 95% confidence interval [CI]: 1.7, 18.3) and 3.6-fold (OR = 3.6; 95% CI: 1.2, 10) more likely in mass (n = 20 for ADH and n = 20 for DCIS) than in non-mass (n = 46 for ADH and n = 97 for DCIS), compared with nonunderestimation, in ADH and DCIS respectively. At multivariate analysis, the use of a 9- or 10-gauge needle versus a 7- or 8-gauge needle was also an independently associated with underestimation when a diagnosis of ADH was made at MR imaging-guided biopsy. No other parameters were associated with of ADH or DCIS upgrade at surgery. Conclusion The rates of underestimation in ADH and DCIS diagnosed at MR imaging-guided vacuum-assisted biopsy were high, at around 25%, and were significantly associated with the presence of a mass at MR imaging. RSNA, 2016.