Comparison of mammography, digital breast tomosynthesis, automated breast ultrasound, magnetic resonance imaging in evaluation of residual tumor after neoadjuvant chemotherapy

Background To compare the accuracy of mammography (MG), digital breast tomosynthesis (DBT), automated breast ultrasound (ABUS) and magnetic resonance imaging (MRI) for the assessment of residual tumor extent in breast cancer after neoadjuvant chemotherapy (NAC). Methods Fifty-one stage II-III breast cancer undergoing NAC were enrolled from March 2015 to December 2016. The longest diameter of residual tumor measured with MG, DBT, ABUS and MRI was compared with the pathologic tumor size. Statistical analysis was performed using intraclass correlation coefficients (ICC) and marginal homogeneity test. Receiver operating characteristics (ROC) analysis was used to evaluate the diagnostic performance for predicting pathologic complete response (pCR). Results MRI size correlated well with pathology (ICC = 0.83), significantly better than MG, DBT and ABUS size (ICC = 0.56, ICC = 0.63 and ICC = 0.55, respectively). The discrepancy between MRI and pathology was statistical different from that of MG and ABUS (p = 0.0231 and 0.0039, respectively), but not different from that of DBT (p = 0.5727). For predicting pCR, MRI and DBT had a better performance compared to MG and US (area under the ROC curve: 0.92, 0.84, 0.72, 0.75, respectively; p = 0.3749 for DBT, p = 0.0972 for MG and p = 0.0596 for ABUS, when MRI being reference). Conclusions MRI and DBT allow more accurate assessment of tumor size compared to pathology compared with MG and ABUS. MRI and DBT outperform MG and ABUS in the prediction of pathologic complete response.