OBJECTIVETo investigate the clinical value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in assessing pathologic responses in breast cancer treated with neoadjuvant chemotherapy.

METHODSForty-five patients with pathologically confirmed breast carcinoma who finished last course of neoadjuvant chemotherapy underwent preoperative breast MRI. All the specimen slices were blindly reviewed by one pathologist. Pathologic response was assessed according Miller & Payne five-point classification, of which grade 5 defined as pathological complete response (pCR) , and grade 5 or 4 defined as major histological response (MHR). DCE-MRI images were blindly reviewed by two radiologists retrospectively on workstation with Functool software. Any non-vessel enhancement in previous tumor bed in any phase of postcontrast acquisition was defined as residual disease. The diagnostic results of two radiologists were correlated to pathological gold standard. Inter-observer consistency was analyzed by Kappa statistics.

RESULTSDCE-MRI for pathological invasive (pINV) residual disease detection in two radiologists had sensitivities of 94.7% and 97.4%, specificities of 42.8% and 57.1%, and accuracy of 86.6% and 91.1%, respectively, while MHR evaluation had sensitivities of 95.5% and 81.8%, specificities of 73.9% and 82.6%, and accuracies of 84.4% and 82.2%, respectively. K values in determine pINV and MHR were 0.728 and 0.778, respectively, showing good inter-observer consistency.

CONCLUSIONDCE-MRI is sensitive in detecting residual breast cancer after neoadjuvant chemotherapy, and can be used to predict the postoperative pathologic response.