Comparison of synthetic mammography, reconstructed from digital breast tomosynthesis, and digital mammography: evaluation of lesion conspicuity and BI-RADS assessment categories.

PURPOSE: To compare the interpretive performance of synthetic mammography (SM), reconstructed from digital breast tomosynthesis (DBT), and full-field digital mammography (FFDM) in a diagnostic setting, covering different conditions of breast density and mammographic signs. METHODS: A retrospective analysis was conducted on 231 patients, who underwent FFDM and DBT (from which SM images were reconstructed) between September 2014-September 2015. The study included 250 suspicious breast lesions, all biopsy proven: 148 (59.2%) malignant and 13 (5.2%) high-risk lesions were confirmed by surgery, 89 (35.6%) benign lesions had radiological follow-up. Two breast radiologists, blinded to histology, independently reviewed all cases. Readings were performed with SM alone, then with FFDM, collecting data on: probability of malignancy for each finding, lesion conspicuity, mammographic features and dimensions of detected lesions. RESULTS: Agreement between readers was good for BI-RADS classification (Cohen's k-coefficient = 0.93 ± 0.02) and for lesion dimension (Wilcoxon's p = 0.76). Visibility scores assigned to SM and FFDM for each lesion were similar for non-dense and dense breasts, however, there were significant differences (p = 0.0009) in distribution of mammographic features subgroups. SM and FFDM had similar sensitivities in non-dense (respectively 94 vs. 91%) and dense breasts (88 vs. 80%) and for all mammographic signs (93 vs. 87% for asymmetric densities, 96 vs. 75% for distortion, 92 vs. 85% for microcalcifications, and both 94% for masses). Based on all data, there was a significant difference in sensitivity for SM (92%) vs. FFDM (87%), p = 0.02, whereas the two modalities yielded similar results for specificity (SM: 60%, FFDM: 62%, p = 0.21). CONCLUSIONS: SM alone showed similar interpretive performance to FFDM, confirming its potential role as an alternative to FFDM in women having tomosynthesis, with the added advantage of halving the patient's dose exposure.

Accuracy of tumour size assessment in the preoperative staging of breast cancer: comparison of digital mammography, tomosynthesis, ultrasound and MRI.

PURPOSE: Accurate measurement of breast tumour size is fundamental for treatment planning. We compared the accuracy of digital mammography (DM), digital breast tomosynthesis (DBT), ultrasound (US) and magnetic resonance imaging (MRI) for the preoperative evaluation of breast cancer size. MATERIALS AND METHODS: We retrospectively reviewed 149 breast cancers in 110 patients who underwent DM, DBT, US and MRI between January 2010 and December 2011, before definitive surgery. The lesions were measured by two radiologists, without knowledge of the final histological examination, considered the gold standard. For each imaging modality, the maximum tumour size was measured to the nearest millimetre; the measurements were considered concordant if they were within ± 5 mm. Pearson's correlation coefficient was calculated for each imaging modality. RESULTS: The median pathological tumour size was 22.3 mm. MRI and DBT had a level of concordance with pathology of 70% and 66%, respectively, which was higher than that of DM (54%). DBT and MRI measurements had a better correlation with pathological tumour size (R:0.89 and R:0.92, respectively) compared to DM (R:0.83) and US (R:0.77). CONCLUSIONS: DBT and MRI are superior to DM and US in the preoperative assessment of breast tumour size. DBT seems to improve the accuracy of DM, although MRI remains the most accurate imaging modality for breast cancer extension.

Preoperative breast cancer staging with multi-modality imaging and surgical outcomes.

PURPOSE: To compare the rates of mastectomy and re-operation after breast-conserving surgery (BCS) among patients who had different pre-operative multi-modality imaging, hence identifying significant predictors of mastectomy and re-operations within each group. METHOD: Retrospective study of consecutive patients with primary breast cancer treated January 2010 - December 2016, divided in 3 groups, undergoing pre-operative local staging respectively with conventional imaging modalities only (2D mammography, ultrasound (US)), conventional imaging and tomosynthesis (DBT) and/or MRI. The primary outcome was identification of significant predictors of surgical outcomes, within each group. Study variables examined in univariate analysis were age, lesion dimension, breast density, multifocality, tumor size, histology, and if associated with outcomes they were included in binary logistic regression analysis. RESULTS: Amongst 1547 patients, patient and tumor characteristics differed across the three groups, as did mastectomy rates which were 18 % (102/562) for 2D + US, 36 % (154/428) for 2D + DBT + US, 45 % (250/557) for 2D+/-DBT + US + MRI(p < 0.001). Variables strongly associated with mastectomy were larger lesions and multifocality (as was multi-modality group). Re-operation rate showed an opposite trend: 12.2 % (56/459) for 2D + US, 8 % (22/272) for 2D + DBT + US, 6.5 % (20/306) for 2D+/-DBT + US + MRI. Re-operation rate for 2D+/-DBT + US + MRI was lower than for 2D + US (p = 0.01) but similar to 2D + DBT + US (p = 0.58). Patients who had 2D + US and re-operations had significantly larger lesions, more underestimation, higher proportion of invasive carcinoma with in-situ component than those who did not require re-operation. CONCLUSIONS: Patients who had larger tumors and multifocal disease were more frequently staged by adding DBT and/or MRI to conventional imaging (mammography and US) which was associated with more extensive surgical treatment but lower reoperation rates.