MRI Screening for High-risk Women
by Kathy Steligo
Hearing that you’re BRCA positive can be quite a shock. Sometimes it’s even tougher to figure out what to do about it.
Deciding how to address risk management can be frustrating and difficult at best. Prophylactic mastectomy is the most effective action, reducing overall breast cancer risk by about 90%. But for many women, it is simply too drastic, both physically and psychologically.
While many women prefer increased surveillance, they worry that monthly self breast exams, semi-annual clinical breast exams, and annual mammograms may not identify breast cancer at an early, treatable stage. Two recent studies show magnetic resonance imaging (MRI) to be an effective adjunctive breast cancer surveillance tool for women with high hereditary risk.
The two studies found MRI, particularly when combined with ultrasound, more effectively detects early stage breast cancer than traditional screening methods. In a Canadian study of 236 women with BRCA mutations, participants were monitored with mammography, clinical breast exam, ultrasound and MRI. While traditional screening tools would have identified less than half of the breast cancers present, MRI found 77%. Mammography identified 36 percent, ultrasound detected 33 percent, and clinical breast exam found just 9 percent. When all four modalities were utilized, 95% of cancers were successfully identified.
A Dutch study of 1,909 women, including 358 with BRCA mutations, had similar results, reinforcing the efficacy of MRI compared to other methods.
In both studies, MRI reliably found both in situ and stage I lesions. The ability to identify these early stage cancers is critical for high-risk, premenopausal women, whose younger, denser breast tissue often obscures mammography. Consequently, their tumors are more frequently highgrade and fast-growing, and are often detected by mammography only after they are advanced.
Although the study results are encouraging, questions remain. MRI appears to offer more sensitive screening of women with BRCA mutations than mammography alone, but we don’t know whether that will ultimately lead to a decrease in breast cancer deaths in this population. Because MRI is more sensitive than mammography, it can pick up abnormalities that aren’t cancer, leading to more biopsies and anxiety.
There are practical issues as well. What combination of screening techniques provides the most effective surveillance? MRI and ultrasound? MRI and mammography? In both studies, MRI and mammography appear to be complimentary; both found in situ cancers missed by the other, and ultrasound found a few additional cases missed completely by MRI. And at what intervals should the different screening procedures be applied? In both studies the MRI screening was performed annually. Cancers developed in some women in the period of time between screenings. These “interval cancers” were detected as lumps found either by the woman or by her physician.
Another issue: like so many other technologies, MRI is only as good as the technician’s experience and the protocol used. And breast imaging is just half of the MRI equation. Lesions identified by MRI that cannot be palpated or detected by mammography or ultrasound require a biopsy using MRI-guidance; traditional methods cannot be used.
Dr. Mark Robson of Memorial Sloan- Kettering Cancer Center, suggests women interested in MRI surveillance research facilities carefully. “Ask how many breast screening MRIs the facility has performed, what their biopsy recommendation rate is, and whether or not they can perform MRI-guided biopsies, so that an abnormality can be sampled if detected,” he recommends.
If you have a BRCA mutation, speak to your doctor about adding MRI and ultrasound to your repertoire of screening tools. While not yet recognized as standard care, some insurance companies now consider MRI screening medically necessary for women with high hereditary breast cancer risk.
Ellen Warner, MD; Donald B. Plewes, et al.
Surveillance of BRCA1 and BRCA2 Mutation Carriers With Magnetic Resonance Imaging, Ultrasound, Mammography, and Clinical Breast Examination. Journal of the American Medical Association. Vol. 292, no. 11, 1317-1325.
Mieke Kriege, Brekelmans CT, et al. (July, 2004)
Efficacy of MRI and Mammography for Breast Cancer Screening in Women with a Familial or Genetic Predisposition. New England Journal of Medicine. Vol. 351, no. 5, 427-437.
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