Predicting nodal status using dynamic contrast-enhanced magnetic resonance imaging in patients with locally advanced breast cancer undergoing neoadjuvant chemotherapy with and without sequential trastuzumab

Hypothesis: Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) is a reliable and accurate method for monitoring primary tumor response in the breast and can be used as a surrogate to predict final axillary nodal status. Design: Retrospective study (October 1, 2004, through February 28, 2006) of 46 patients with clinically staged locally advanced breast cancer. Patients: Forty-six patients with locally advanced breast cancer. Interventions: Neoadjuvant chemotherapy (NAC), DCE-MRI, mastectomy and lumpectomy, and axillary lymph node dissection. Main Outcome Measures: The DCE-MRI results and pathologic response of the breast and axillary lymph nodes. Results: Forty-six patients underwent NAC with doxorubicin hydrochloride and cyclophosphamide, followed by paclitaxel and carboplatin, with or without trastuzumab based on human epidermal growth factor receptor 2 (HER2/neu) status. Twenty-one patients (46%) had a complete pathologic response. For the HER2/neupositive patients, the complete pathologic response rate was 70% (14/20). The accuracy, sensitivity, and specificity of the primary tumor response in predicting the axillary nodal status were 78%, 88%, and 72%, respectively. The accuracy, sensitivity, and specificity of the DCE-MRI-measured response in the primary tumor in predicting axillary nodal status were 74%, 62%, and 82%, respectively. For the HER2/neu-positive patients, the accuracy, sensitivity, and specificity improved to 80%, 75%, and 82%, respectively. Conclusions: The results of DCE-MRI of the primary tumor can be predictive of axillary nodal status, especially in patients receiving trastuzumab who are HER2/ neu positive. The HER2/neu-positive patients with a complete clinical response on DCE-MRI are highly unlikely to benefit from an axillary lymph node dissection. For HER2/neu-negative patients, sentinel lymph node sampling is warranted.