Monitoring of Breast Cancers Treated by Neoadjuvant Therapy Via Diffusion-weighted Magnetic Resonance Imaging

Overview

Magnetic resonance imaging (MRI) is the method of choice in breast cancer to perform the loco-regional staging and direct the treatment. European Guidelines (EUSOMA) currently recommend MRI for initial evaluation and assessement of the neoadjuvant chemotherapy (NAC) response, for breast cancer. The standard of care consists of realizing a MRI before the start of the NAC and another one after it's ended, six months later. There is currently no consensus on the realization of an interval MRI for early assessment of the chemosensitivity of the tumor. It would allow though alterations in the therapeutic regimen in the event of a non response. Similarly, there is no consensus on when this interval MRI should be performed. Some recent studies suggest that Diffusion-weighted Magnetic Resonance Imaging is interesting for the evaluation of the early response. However, these are preliminary studies with quantitative measures realized by the region of interest (ROI) method. A response to neoadjuvant chemotherapy results in elevated values of apparent diffusion coefficients (ADC). The investigator's goal for this study is to evaluate the reliability of diffusion as tumor biomarker. Therefore, they will study the quantitative analysis of the diffusion-weighted magnetic resonance sequences in the pre-therapeutic assessment and the early and late follow-up of breast cancers under neoadjuvant treatment (chemotherapy, hormonotherapy...) within the CHU Brugmann hospital. The results of this analysis will be compared with the MRI results obtained at the end of the treatment and with the histology of the initial biopsy and the surgical specimen. The expected benefits are: * to establish correlations between apparent diffusion coefficients (ADC) values and histology * to observe changes in the ADC according to the type of response: ADC increase in the event of partial response, ADC stability in the event of non response, ADC decrease in the event of a progression, absence of restriction in the event of a complete response. * to confirm that diffusion weighted MRI within a short interval (after one cure, at one month) has a predictive value for the neoadjuvant chemotherapy (NAC) response.