Preoperative MRI in Newly Diagnosed Breast Cancer Shows Little Benefit

Researchers from the University of Sydney, Australia, and the University of Michigan Comprehensive Cancer Center have reported that preoperative magnetic resonance imaging (MRI) in breast cancer leads to more extensive surgery without evidence of improvement in surgical outcomes or long-term prognosis. The details of this study appeared in CA: A Cancer Journal for Clinicians.

Preoperative MRI is increasingly being used in women with early-stage breast cancer who are undergoing breast-conserving surgery (lumpectomy) in order to detect additional areas of disease that may need to be removed but weren’t detectable with conventional imaging. The use of preoperative MRI is based on the assumption that it improves surgical planning, reduces follow-up surgery, and reduces the risk of local recurrence. However, this study indicates that MRI actually changes surgical management to more radical surgery.

Researchers performed a meta-analysis of more than 20 studies evaluating the impact of MRI on detection and surgical treatment in women with early-stage breast cancer. They found significant variability in the detection of additional areas of cancer, with MRI-only detection varying between 1% and 28% for cancers with more than one tumor and 2% and 15% for cancers with more than one tumor that have formed separately from one another.

Furthermore, the review indicated that women who underwent preoperative MRI were more likely to have a wider excision or mastectomy instead of the initially planned lumpectomy. This more extensive surgery, however, did not necessarily lead to better surgical outcomes.

These researchers concluded that more research is needed—in the form of randomized, controlled trials—to evaluate preoperative MRI in breast cancer patients. In the meantime they conclude that MRI causes false-positives and unnecessary surgery and does not appear to reduce re-excision rates. They assert that preoperative MRI may actually do more harm than good.

Comments: This is obviously a controversial topic, as other studies have found preoperative MRI to be useful in determining optimal extent of breast cancer surgery.

Reference: Houssami N, Yayes DF. Review of preoperative magnetic resonance imaging (MRI) in breast cancer: Should MRI be performed in all women with newly diagnosed, early stage breast cancer? CA: A Cancer Journal for Clinicians [early online publication]. August 13, 2009.