MRI Evaluation of Residual Breast Cancer After Neoadjuvant Chemotherapy: Influence of Patient, Tumor and Chemotherapy Characteristics on the Correlation with Pathological Response

Aim: The aim of this study was to evaluate the correlation between the residual tumor measured on magnetic resonance imaging and pathological results and to assess whether this correlation varies according to patient, tumor or chemotherapy characteristics. Patients and Methods: The study population included women treated for breast cancer with indication of neoadjuvant chemotherapy in our tertiary breast cancer Unit between January 2008 and December 2011. Factors related to patients, tumor and chemotherapy were studied. Pearson's correlation coefficient between the size of the tumor on MRI and pathological response was calculated for the entire population. It was also calculated according to patient, tumor and chemotherapy characteristics. Results: During the study period, 107 consecutive women were included. The size of residual tumor on the MRI significantly correlated with the size on pathological result with a Pearson correlation coefficient of 0.52 (p<0.001). The correlation was stronger for women aged 50 years and older (r=0.64, p<0.001) and for postmenopausal women (r=0.61, p<0.001). The correlation was stronger for those with triple-negative tumors (r=0.69, p=.0.002) but weaker for those with tumors with a ductal carcinoma in situ component (r=0.18, p=0.42). Conclusion: The size of breast cancer obtained by MRI is significantly correlated to the pathological size of the tumor. This correlation was stronger among women aged 50 years and more, among post-menopausal women, and among women who had triple-negative tumors.