Role of Magnetic Resonance Imaging in the prediction of tumor response in patients with locally advanced breast cancer receiving neoadjuvant chemo-therapy.

Purpose: To evaluate if dynamic contrast enhanced magnetic resonance can predict the tumoural response in patients with breast cancer undergoing neoadjuvant chemotherapy.

Materials And Methods: Twenty-six patients with biopsy-proven locally advanced breast cancer underwent taxane-based neoadjuvant chemotherapy followed by radical surgery. MRI evaluations were carried out at baseline, after two of the four planned cycles of chemotherapy, and before surgical treatment. MR images, obtained with 1.5 T scanner and using dedicated surface multichannel coil (GEMS), were acquired by 3D SPGR sequences on the coronal plane before and after intravenous administration of gadolinium chelate by an automatic injector. The percent reduction of the early contrast uptake between the baseline and the second MRI was then calculated for every lesion and correlated with the outcome of interest (pCR).

Results: At baseline, we identified 26 lesions and two patterns of MRI enhancement: homogeneous (group 1, 14 patients) and peripheral ring-like (group 2, 12 patients). At surgery, pathological complete response was observed in 4 patients (2 patients group 1, 2 patients group 2). In group 1, the 2 cases of pCR showed a gs;70% reduction in the early contrast uptake between baseline examination and after two cycles of chemotherapy, whereas values <70% were seen in 12 cases of partial response (p=0.02). In group 2, the 2 cases of pCR showed a gs; 40% reduction in the early contrast uptake whereas all of the 10 cases of partial response had <40% reduction (p=0.02).

Conclusions: In our series, the percent reduction in the early contrast uptake after two cycles of neoadjuvant chemotherapy was predictive of the achievement of a pathological complete response. However, we identified two distinct morphologic patterns associated with different cut-offs in the predictive value of the early contrast uptake reduction between baseline and intermediate examination.