Women at High Risk of Breast Cancer Advised to Get MRIs
Regular mammography is still the gold standard when it comes to breast cancer screening, but more than a million women at particularly high risk of developing the disease should add magnetic resonance imaging to the annual mix. That's the bottom line of two reports released today, one by the American Cancer Society and the other a study appearing in the New England Journal of Medicine.
The ACS report updates its recommendations for breast cancer screening. Based on the results of studies released over the past few years, it now advises women with a lifetime risk of between about 20 percent and 25 percent to have an annual MRI on top of mammography. Women who fall into that group include those with the rare but dangerous BRCA mutations; those who have mothers, sisters, or daughters with the mutations; others with a very strong family history of the disease, and women treated with chest radiation between the ages of 10 and 30. These women should begin annual screening with both mammography and MRI at age 30, the ACS said in the report, published in CA: A Cancer Journal for Clinicians.
Another group who should add MRI to the screening regimen, says the NEJM study, are women recently diagnosed with cancer in one breast. MRI more effectively finds cancer in the other breast, the study says. Researchers studied 969 women whose mammograms and clinical exams found no problems in the other breast, and discovered that MRI spotted cancer in 30 of those women. It missed only three cancers (later found during a mastectomy), meaning that, once scanned, women can have a high level of confidence that they do not have cancer in that breast. Constantine Gatsonis, an author of the study and director of Brown University's Center for Statistical Sciences in Providence, R.I., says he expects that the results will immediately influence practice. "In general, if anyone has cancer in one breast, she should go ahead and get an MRI in the other," he says.
MRI is not perfect: It sometimes flags harmless areas as suspicious, leading to unnecessary biopsies and worry, and may miss calcium deposits, an early sign of ductal breast cancer detectable by mammography. That's why it's used in combination with the older test, and why it is not advised for everyone. Unless a woman is at high risk for the disease, experts say, there will simply be too many false-positive results and not enough additional benefit. "This does not generalize to the woman on the street," says Gatsonis. MRI is also expensive, ranging from $800 to $1,500 compared with a 10th of that for mammograms. The cost won't be covered by insurance unless you fall into the high-risk groups. The test can also be hard to find.
Christy Russell, chair of the ACS's Breast Cancer Advisory Group and co-director of the USC/Norris Breast Center in Los Angeles, says that for these at-risk women, an MRI is definitely worth seeking out but that there's no need to do it immediately. They can wait until their next mammogram and have the tests done concurrently.
The ACS report says there's not enough evidence to recommend for or against MRI screening for women who previously had breast cancer, those with certain abnormal cells in the breast that boost the risk of cancer, or those with dense breasts. Anyone who falls into any of these groups may want to talk to her doctor about possible screening.