The Role of MRI Before Breast Conservation

Breast conserving therapy comprising excision of the malignancy followed by irradiation is the method of choice for the treatment of small breast cancer. Increasing data show that contrast-enhanced breast MRI may be useful to more correctly assess tumor extent in cases scheduled for breast conserving therapy. Existing data prove that MRI can detect foci or extent of both invasive and in situ breast cancer not visualized by mammography or ultrasound. A correct change of therapy (with respect to complete excision of malignant tissue) has been reported in approximately 12% to 32% of the examined breast cancers. However, this is associated with a reported rate of 3% to 30% of false positive calls, which necessitate additional percutaneous or open biopsy, or wider excision. The best proportion of true positive versus false positive findings may be expected in patients with proven lobular invasive breast cancer or in patients with dense breast tissue at increased risk. So far valid data concerning an effect on improved survival or a decreased rate of recurrence do not exist. Open questions, such as value for the patient, potential over-treatment and the need to assure adequate guidance for histopathological assessment of MR-detected lesions are discussed.