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Annual MRI is the screening test of choice for all women over 30 with BRCA mutations Multiple prospective studies have shown than MRI is much more sensitive than mammography for screening women with BRCA mutations. However, since MRI is much more expensive than mammography and has a 2 - to 3-fold higher rate of false positive results, finding a subgroup whom mammography alone might be adequate would be highly desirable. Unfortunately, this study showed that even in women with low breast density, measured either qualitatively or quantitatively, mammography detected only 37% to 43% of invasive breast cancers, compared to a 90% detection rate for MRI. Furthermore, mammography missed 80% of the cases of DCIS detected by MRI regardless of breast density. There are several possible explanations for these findings. Since tumours grow more quickly in women with BRCA mutations than in women with non-BRCA cancers, and grow more quickly in younger than in older women, calcification of the malignant ducts - an important mammographic feature of malignancy -may not have had time to occur. Also, BRCA1-related tumours tend to be fleshier with less fibrous tissue than other breast cancers, which might decrease mammographic visibility. Finally, even in women with generally fatty breasts, there may be scattered areas of higher breast density where tumours would be obscured. Although digital mammography was not used in this study, it would not be expected to be superior to film-screen mammography for fatty breasts. Tomosynthesis, a 3-dimensional mammographic technique under development, might hold promise for screening high-risk women, particularly if a contrast agent sensitive to angiogenesis is used, as is currently routine with MRI. For now, annual MRI (added to mammography) is the screening test of choice for all women over 30 with BRCA mutations or a very strong family history of breast cancer
Bibliographic Reference:
Ellen Warner Toronto-Sunnybrook Regional Cancer Center, Toronto, Ontario, Canada
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