About 10% of all breast cancer cases occur on a hereditary
basis. BRCA1/2 (breast cancer oncogenes) account
for about 50% of all hereditary breast cancer cases. The
remaining cases of suspected inherited origin given by
family histories might be associated with other known or
currently unknown genes. Deleterious mutations in the
BRCA1 or BRCA2 genes are associated with an increased
life-time risk of breast and ovarian cancer. BRCA1/2 carriers
are more likely in to develop breast cancer at a young
age compared with the general population. For women
at high breast cancer risk with a mean age under 40
years at diagnosis reported sensitivities of mammography
and ultrasound are low, ranging around 30-40%.
Using magnetic resonance imaging (MRI) as a complementary
imaging tool the sensitivity may increase to
90%. However, the specificity of MRI appears to be generally
lower than that of mammography and ultrasound.
The data differ depending on patient selection and study
design. However, all studies indicate that contrast enhanced
magnetic resonance imaging may be the most
promising method. Further investigations are still needed
to minimize the false-postive rate and to investigate
the efficacy of MRI as an integral screening modalitiy in
the surveillance of women with increased breast cancer
susceptibility.
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