Dynamic enhanced MRI predicts chemosensitivity in breast cancer patients.

BACKGROUND: Primary chemotherapy for breast cancer is effective as postoperative adjuvant therapy. However, one of the critical disadvantages was a treatment delay for patients with progressive disease. The present study attempts to clarify quantitative parameters on MRI which can be used to predict the sensitivity to treatment in breast cancer patients.
METHODS: The subjects consisted of 26 patients with invasive ductal breast cancer who received primary chemotherapy before surgery. The mean maximum tumor dimension was 3.3cm, and 21 cases had nodal involvements. Three cases demonstrated histological grade 3. Dynamic enhanced MRI was evaluated at three different time periods; prior to, in the midst of preoperative chemotherapy, and just before the initial operation. The signal intensity ratio (SIR) and early contrast uptake (ECU) were calculated, as well as the correlation between these dynamic data and the tumor reduction rates were analyzed retrospectively. P-values of less than 0.05 were considered to indicate statistically significant.
RESULTS: Responders to chemotherapy had the significantly higher SIR and ECU values than non-responders (p=0.0454 and 0.0334, respectively). ECU value significantly decreased as tumor reduction by chemotherapy (p=0.0028). Pathological tumor dimension was significantly correlated with the tumor size estimated on presurgical MRI (p<0.0001).
CONCLUSIONS: Our current series demonstrated the significant correlation between pretreatment MRI data and tumor reduction by chemotherapy in breast cancer patients. With these results, it seems possible to define good and non-responders prior to treatment.