Breast Cancer MRI: Is It Necessary?

Breast cancer is diagnosed in nearly 185,000 Americans each year and kills close to 41,000, according to estimates by the American Cancer Society. Since early detection is of paramount importance, yearly mammograms are recommended starting at age 40. Because it is more sensitive, magnetic resonance imaging (MRI) of the breast is recommended, in addition to the yearly mammography, for younger women at high risk of developing breast cancer, such as those who test positive for the BRCA1 or BRCA2 gene, or who have a strong family history of breast or ovarian cancer. Breast MRIs are also increasingly used in women newly diagnosed with breast cancer. However, new research suggests that routine use of MRIs in this instance may not only be unnecessary for most women, but may have distinct disadvantages. “MRI may not be as good as we think it is,” said Dr. Richard J. Bleicher, co-director of the breast surgery fellowship at Fox Chase Cancer Center in Philadelphia.

In an effort to access what impact the breast MRIs have on a woman’s care, Dr. Bleicher and colleagues reviewed records of 577 breast cancer patients who had been evaluated by a radiologist, pathologist, and a surgical, radiation and medical oncologist. Of these patients, 130 had MRIs prior to treatment. The researchers found that the women who had gotten an MRI delayed treatment by average of 22.4 days. Dr. Bleicher said while he cannot say whether a three-week delay in surgery would influence a patient’s chance of survival, he was sure it would “increase the anxiety on her part.”

The MRI group were also far more likely (80 percent after adjusting for tumor size) to get a mastectomy instead of the lesser lumpectomy. These findings reinforce those of a study presented earlier this year by Mayo Clinic doctors. Dr. Bleicher said it isn’t clear why these women chose mastectomy but it may be related to the higher sensitivity of the MRI’s, which leads to a high instance of false-positive findings. “Rather than having a biopsy to see if those findings are real, women and their doctors may choose mastectomy out of an abundance of caution,” he said. “Many of the mastectomies are later proven by pathology to have been unnecessary.”

In addition, having routine pretreatment MRIs did not improve a woman’s outcome. Dr. Bleicher said studies have long shown that women are equally likely to survive whether they have mastectomies or lumpectomies plus radiation. “There’s been a lot of hype about MRI. It is more sensitive . . . and people have assumed that because it is more sensitive that it will improve outcomes in women either for screening or breast cancer, but there’s just about no data to suggest that,” he said. “MRI’s are valuable and should be done in certain women at high risk, but they are not appropriate in routine evaluation of breast cancer.”

Other experts say it is too early to know if MRIs really affect survival and that larger studies should be allowed to develop over time in order to see the effect. “It’s not a cut-and-dried issue,” said Debbie Saslow, director of breast and gynecologic cancer at the American Cancer Society. “We need more research before we come up with a general recommendation.”

Dr. Bleicher presented his findings September 6 at the American Society of Clinical Oncology’s Breast Cancer Symposium in Washington.