MRI Around the Time of Surgery Does Not Reduce Recurrence Rates in Women With DCIS
A large retrospective study reported that adding magnetic resonance imaging (MRI) to mammography before or immediately after surgery was not associated with reduced local recurrence or contralateral breast cancer rates among women with ductal carcinoma in situ (DCIS) of the breast who were treated with lumpectomy. The findings (Abstract 57), which will be presented on Saturday, September 7, at the 2013 Breast Cancer Symposium, suggest that MRI does not improve long-term outcomes for most women with DCIS, and may lead to a decrease in routine use of MRI in this patient population.
High False-Positive Rate
There are no published clinical practice guidelines on the use of MRI in women with newly diagnosed breast cancer. Therefore, overall use of MRI for patients with breast cancer varies by hospital and individual surgeon. A recent survey of U.S. surgeons reported that 37% routinely use MRI for patients with DCIS. Surgeons at academic institutions were less likely to refer patients with newly diagnosed breast cancer to MRI testing compared private practice surgeons.
“We now have a lot of evidence that indicates that MRI isn’t necessary for every patient with DCIS. Aside from the cost of the test, MRI has a rather high false-positive rate, which may result in additional biopsies and a delay in surgery,” said first study author Melissa L. Pilewskie, MD, a breast surgeon at Memorial Sloan-Kettering Cancer Center in New York and Commack, New York. “We need to focus on spending money and time on tests that we know are going to provide benefit.”
Study Details
Researchers evaluated locoregional recurrence rates among 2,321 women who underwent a lumpectomy for DCIS between 1997 and 2010 at Memorial Sloan-Kettering Cancer Center. In that cohort of patients, 596 had received an MRI either before or immediately after their surgery, and 1,725 had not. The women were followed for a median period of 59 months. The differences in 5-year locoregional recurrence rates were not statistically significant between those two groups of women (8.5% with MRI vs 7.2% without MRI). The 8-year recurrence rates were also not significantly different (14.6% vs 10.2%).
Even after controlling for patient characteristics and factors linked to risk of recurrence (age, menopausal status, family history, clinical presentation, use of adjuvant endocrine therapy or radiation, surgical margin status, and number of excisions), MRI was still not associated with lower locoregional recurrence rates. Researchers also found no statistically significant differences in rates of contralateral breast cancer at 5 years (3.5% in both groups) or 8 years (3.5% in the MRI group and 5.1% in the mammography-only group).
Women in MRI Group More Likely to Have Higher-Risk Disease
Women who had an MRI were younger and more likely to be pre- or perimenopausal, to have a family history of breast cancer, and to receive radiation and hormonal therapy. Many of these factors are also associated with higher-risk disease, which may explain the slightly higher recurrence rates in that group compared to those who did not have an MRI, even though use of endocrine and radiation therapy decrease the risk of recurrence. Dr. Pilewskie stated that one could also assume that the same risk factors prompted doctors to order an MRI for those patients.
Most women with DCIS who receive MRI around the time of surgery, have the scan before surgery to assess the extent of the disease. On occasion, a woman may have an MRI after surgery to look for any residual disease in the breast and/or plan for reexcision, if positive margins are found after lumpectomy. In this study, most women (81%) who had an MRI received it before surgery.
Previous studies have shown that use of MRI does not decrease reexcision rates for women with DCIS. Together with the present study, these findings indicate that MRI is not associated with improved short-term or long-term outcomes for these patients. According to Dr. Pilewskie, future research should focus on areas where use of MRI is likely to improve patient care and outcomes—such as monitoring the response to neoadjuvant chemotherapy—rather than in routine preoperative management of patients.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
