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MRI Might Improve Breast Cancer Screening in High-Risk Women

Findings of a British study indicate that MRI might be a useful adjunct to mammography in high-risk women, especially those with BRCA1 mutations.

Women who are at high risk for breast cancer because of genetic predisposition are advised to have annual mammograms starting at age 30, but mammograms are relatively insensitive in young women with dense breasts. Contrast-enhanced magnetic resonance imaging (MRI) is more sensitive but less specific than mammography in such women.

Investigators in the U.K. performed 1881 paired mammograms and contrast-enhanced MRI studies on 649 asymptomatic women (age at entry, 31–55) with known BRCA1, BRCA2, or TP53 mutations or a strong family history of breast cancer. Suspicious findings were evaluated until malignancy was confirmed (35 exams) or excluded (244 exams).

MRI was significantly more sensitive (77% vs. 40%) but less specific (81% vs. 93%) than mammography. Combined, the two tests had a sensitivity of 94% but a specificity of only 77%. When women or their first-degree relatives had BRCA1 mutations, MRI was much more sensitive than mammography (92% vs. 23%). In women with other risk factors, MRI was not significantly more sensitive than mammography.

Comment: Like results from two other studies (Journal Watch Oct 5 2004 and Journal Watch Aug 10 2004), these results suggest that MRI might be a useful adjunct for breast cancer screening in high-risk women, particularly those with BRCA1 mutations. Because no evidence yet exists showing that MRI screening will reduce breast cancer mortality in this population, the uncertain value of MRI must be weighed against its high cost and the excess diagnostic procedures that result from its lower specificity.

— Bruce Soloway, MD

Published in Journal Watch General Medicine June 21, 2005

Citation(s):

Leach MO et al. Screening with magnetic resonance imaging and mammography of a UK population at high familial risk of breast cancer: A prospective multicentre cohort study (MARIBS). Lancet 2005 May 21; 365:1769-78.

• Medline abstract (Free)

Warner E and Causer PA. MRI surveillance for hereditary breast-cancer risk. Lancet 2005 May 21; 365:1747-9.

• Medline abstract (Free)