Increased use of MRI for breast cancer surveillance and staging is not associated with increased rate of mastectomy.

The use of MRI in preoperative staging of breast cancer has escalated recently. Breast MRI has greater sensitivity than mammography, ultrasound, and clinical examination in cancer detection. Because of its variable specificity, however, there has been concern that increased MRI use will result in increased rates of mastectomy for early-stage breast cancer. We postulated that mastectomy rates are not affected by trends in MRI use. We performed a retrospective analysis of imaging tests ordered by surgeons at our breast center from 2003 to 2007. We also reviewed all breast cancer cases reported to the National Cancer Database from our institution during the same time period and categorized them as having been treated with mastectomy or breast-conserving surgery. From 2003 to 2007, the number of breast MRIs ordered annually by surgeons increased from 68 to 358. The rate of MRI use increased from 4.1 per every 100 patients seen to 5.7 and from 1.6 per every 100 new patients seen to 2.9. The percentage of women undergoing mastectomy for breast cancer remained unchanged during this 5-year interval. Therefore, although MRI use in breast cancer staging and surveillance has increased, mastectomy rates have not.