Imaging in evaluation of response to neoadjuvant breast cancer treatment benefits of MRI

Purpose. To compare the value of conventional imaging modalities and MRI for determination of response to neoadjuvant chemotherapy for breast cancer. Material and methods. Sixty tumors (53 ductal carcinomas, seven invasive lobular carcinomas) in 51 patients were evaluated by physical examination, mammography, ultrasound, and MRI at baseline before therapy, after three courses of chemotherapy, and after six courses prior to surgery. Data from physical examination and imaging studies were compared to histopathological findings. Results. (i) MRI was the most reliable technique for evaluation of residual tumor size; this parameter was correctly estimated in 63% of cases by MRI versus, respectively 52, 38, and 43% by physical examination, mammography, and ultrasound, (ii) MRI correctly identified the response to chemotherapy in all cases of complete response (five cases), and in 45/55 cases of partial response (43 cases) or no response (12 cases), and (iii) among the 32 patients who underwent a mastectomy, MRI correctly revealed the multifocal nature of the disease for 12/15 multifocal lesions found at histological examination; both mammography and sonography were accurate in only six of the 15 cases. Conclusion. MRI appears to be a valuable technique for assessment of response to chemotherapy and identification of multifocal disease prior to surgery.