Background
New guidelines from the American Cancer Society (ACS) recommend the use of magnetic resonance imaging (MRI) for screening women at high risk for breast cancer. Additionally, a study of breast MRI in women with newly diagnosed breast cancer suggests that breast MRI may also play a role in this population.

The Guidelines
According to the ACS guidelines, routine breast cancer screening with mammograms and MRI is recommended for women at high risk for breast cancer. High-risk features include a BRCA1 or BRCA2 gene mutation, a strong family history of breast or ovarian cancer, a 20% or greater lifetime risk of breast cancer, and radiation therapy to the chest for the treatment of lymphoma.

The Study
In the NEJM study, 969 women with unilateral breast cancer underwent a breast MRI in the contralateral breast soon after diagnosis. Although no abnormalities were found by clinical examination or mammography, MRI detected abnormalities in the unaffected breast in 121 patients (13%). In follow-up biopsies of women with positive MRI findings, 30 patients (25% of those receiving biopsies; about 3% of the total study group) were found to have invasive breast cancer.

Additional perspective on the ACS guidelines:
Julie Gralow, MD, Associate Professor of Medicine/Oncology at the University of Washington School of Medicine and Fred Hutchinson Cancer Research Center in Seattle, supports screening for high-risk women, but is worried about the quality of breast MRI tests. "Breast MRI vastly differs in quality from center to center. Currently, there are no standards. Many poor-quality MRIs are being done in those who don't have the equipment, experience, or guidance, which can falsely reassure women who may actually have breast cancer or, alternatively, falsely suspect cancers in women without cancer, leading to excessive, unnecessary biopsies and surgeries. New standards that may help address this concern are coming out within the next year from the American College of Radiology.

As with other screening tests, breast MRIs have limitations: they are about ten times as expensive as mammograms, and the data supporting screening MRI are not as strong as data supporting screening mammography. Breast MRI has not yet been well studied in women with an average risk for breast cancer and is not recommended for those women."

"The ACS guidelines are an appropriate resource for clinicians. The key is that technology is increasing our ability to detect and treat cancer when it is at its most curable stage," said Clifford A. Hudis, MD, Chief, Breast Cancer Medicine Service and Associate Attending Physician at Memorial Sloan-Kettering Cancer Center in New York City. "It is important, though, that the breast MRI facility has the capacity to perform follow-up biopsies."

On the NEJM study:
"This study is reasonable, and it may change clinical practice," said Eric Winer, MD, Director, Breast Oncology Center at the Dana-Farber Cancer Institute and Associate Professor of Medicine at Harvard Medical School in Boston. "It doesn't mean that every woman with breast cancer should have an MRI of the other breast at the time of diagnosis, however. We need to discuss this topic with our patients."

Bottom line
"MRI can be considered as another option for women at high risk of developing breast cancer, but an MRI cannot be substituted for mammography. Women concerned about getting this test should talk with their physicians and find centers with experience in performing and interpreting breast MRIs," said Dr. Gralow.

For more information: Resources on this topic include the Cancer.Net Guide to Breast Cancer and the Cancer.Net Feature: Magnetic Resonance Imaging—What to Expect.

References

MRI Evaluation of the Contralateral Breast in Women with Recently Diagnosed Breast Cancer. NEJM, Published online at http://content.nejm.org/cgi/content/short/NEJMoa065447
(Issue available March 29, 2007)

American Cancer Society Guidelines for Breast Screening with MRI as Adjunct to Mammography
Available at: http://caonline.amcancersoc.org/cgi/content/full/57/2/75