In a significant announcement, the American Cancer Society (ACS) has amended its breast-screening guidelines to include magnetic resonance imaging (MRI) tests for high-risk individuals.

According to the ACS announcement, “Certain women with an especially high risk of developing breast cancer should get magnetic resonance imaging (MRI) scans along with their yearly mammogram, according to a new American Cancer Society guideline. The two tests together give doctors a better chance of finding breast cancer early in these women, when it is easier to treat and the chance of survival is greatest.”

However, the ACS also made it clear that the use of MRIs should be relegated only to a subset of patients who have high risk factors. “As with other cancer screening tests, MRI is not perfect and in fact leads to many more false-positive results than mammography,” says Dr. Christy Russell, chair of the ACS Breast Cancer Advisory Group and co-author of the new guideline. Estimates put the frequency of false-positives as high as 11 percent. “Those false-positives, which can lead to a high number of avoidable biopsies, can create fear, anxiety, and adverse health effects, making it imperative to carefully select those women who should be screened using this technology.”

According to the newly released guideline document, “New evidence on breast Magnetic Resonance Imaging (MRI) screening has become available since the American Cancer Society (ACS) last issued guidelines for the early detection of breast cancer in 2003. A guideline panel has reviewed this evidence and developed new recommendations for women at different defined levels of risk. Screening MRI is recommended for women with an approximately 20–25 percent or greater lifetime risk of breast cancer, including women with a strong family history of breast or ovarian cancer and women who were treated for Hodgkin disease.”

Among the important new evidence is the result of a study known as the American College of Radiology Imaging Network (ACRIN) study, which was supported by the National Cancer Institute (NCI) and is to be published this week in the New England Journal of Medicine. The ACRIN study determined that “Magnetic Resonance Imaging (MRI) scans of women who were diagnosed with cancer in one breast detected over 90 percent of cancers in the other breast that were missed by mammography and clinical breast exam at initial diagnosis,” according to a report by the NCI. They also note that “adding an MRI scan to the diagnostic evaluation effectively doubled the number of cancers immediately found in these women.”

The study included more than 1,000 women who were recently diagnosed with cancer in one breast. All of the women in the study had received a negative mammogram and negative clinical breast exam of the opposite breast within 90 days of the MRI. However, 33 of these women were eventually diagnosed with contralateral breast cancers, 30 of which (91 percent) were discovered as a result of MRI.

“Researchers found that the added benefit of MRI was consistent, regardless of a woman’s cancer type, age, or breast density,” the NCI reports.

The new ACS screening guidelines don’t apply to all women, but they will affect approximately 1.6 million women in the United States. The recommendation for annual MRI screening applies to women in the following categories: have a BRCA1 or BRCA2 mutation; have a first-degree relative (parent, sibling, child) with a BRCA1 or BRCA2 mutation, even if they have yet to be tested themselves; have a lifetime risk of breast cancer that has been scored at 20 to 25 percent or greater, based on one of several accepted risk assessment tools that look at family history and other factors; have had chest radiation between the ages of 10 and 30; have Li-Fraumeni syndrome, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome, or may have one of these syndromes based on a history in a first-degree relative.

The ACS said that researchers have not yet determined that the MRI screening offers benefits to women with lower risk factors, although research is still pending on that matter.

This entry was posted on Wednesday, March 28th, 2007 at 1:02 pm and is filed under Health Concerns.