According to the results of a study published in the Archives of Surgery, use of magnetic resonance imaging (MRI) before breast surgery resulted in a beneficial change to surgical plans in roughly 10% of women with newly diagnosed breast cancer, and an unnecessary change to surgical plans (resulting in more extensive surgery) in 14% of women.
Magnetic resonance imaging (MRI) uses radio waves and a magnet to create detailed images of the inside of the body. The American Cancer Society now recommends that women at high risk of breast cancer undergo yearly breast cancer screening with breast MRI in addition to mammography. These recommendations were prompted by several studies of MRI screening of women at high risk of breast cancer. While these studies found that the addition of MRI to mammography increased the frequency of false-positive test results compared to mammography alone, it also produced important improvements in breast cancer detection.
In addition to playing a role in breast cancer screening, MRI may also influence treatment decisions in newly diagnosed women. To explore whether use of preoperative breast MRI changes the surgical management of women with breast cancer, researchers conducted a study among 155 newly diagnosed women.
• The MRI prompted follow-up mammograms or ultrasounds in 65 women, and 41 women underwent additional biopsies.
• 36 women (23% of the total) had a change in surgical plans as a result of the MRI.
• In 10 women MRI findings changed the surgical plan from lumpectomy to mastectomy. It eight of the 10 women, evaluation of the tissue that was surgically removed confirmed that the change in surgical plan was beneficial to the patient.
• In 21 women MRI findings led to removal of more breast tissue (wider excision) than originally planned. In five of the 21 women this change was believed to be beneficial.
• Five women underwent surgery to the contralateral (opposite) breast as a result of MRI findings, and cancer was found in two of the five cases.
In summary, of the 36 women who had a change to more extensive breast surgery as a result of preoperative MRI, the change was ultimately found to be beneficial in 15 of the women. Although the researchers conclude that breast MRI may have a role in the evaluation of new breast cancers, the risk of overtreatment must be considered as well.
Reference: Bilimoria KY, Cambic A, Hansen MN, Bethke KP. Evaluating the impact of preoperative breast magnetic resonance imaging on the surgical management of newly diagnosed breast cancers. Archives of Surgery. 2007;142:441-447.