A clinical oncologic perspective on breast magnetic resonance imaging

Magnetic resonance (MR) imaging identifies cancer not found by clinical examination or other breast imaging studies, but its effect on patient outcomes is controversial. To date, its use has not been shown to increase the likelihood of obtaining negative surgical margins, decrease the rate of conversion from lumpectomy to mastectomy, or decrease local recurrence. The rate of tumor identification with MR imaging is 2 to 3 times higher than the incidence of local recurrence, resulting in mastectomies that may not be beneficial to the patient. This is also a concern with the use of MR imaging for contralateral cancer detection. The use of MR imaging for early detection of local recurrence does not take into account what is known about the biology of local recurrence because a short interval to local recurrence is associated with poor prognosis. In problem areas, such as evaluation of response to neoadjuvant therapy and detection of cancer presenting as axillary adenopathy, MR imaging provides information that is useful for clinical management.