| MRI should be considered an integral part of any surveillance program for women with a familial risk for breast cancer
Our results suggest that
Magnetic Resonance Imaging is the most accurate tool for screening women
at increased familial risk for breast cancer, notably not only for women
with a documented mutation in a so-called "breast cancer
susceptibility gene" (BRCA), but also for women without such a
mutation. This is important since only a very small fraction of women
with a personal or family history of breast cancer will in fact be
diagnosed with a BRCA mutation - the vast majority will test negative
for any of the known mutation.
Our study shows that with breast
MRI we are able to diagnose
breast cancers at a very early stage, and long before the tumors are
visible by either mammography and breast ultrasound. Accordingly, our
data suggest that MRI should also be considered an integral part of any
surveillance program for women with a familial risk for breast cancer.
If MRI is performed with a level of expertise that is about
equivalent to the expertise with which mammograms are read, MRI does not
lead to a high rate of unnecessary biopsies (for false-postive findings)
but it does in fact even allow to reduce (!) the diagnostic errors made
with mammography in this specific subset of women.
If
a BRCA mutation has been documented, it is relatively straightforward to
predict the lifetime risk of breast cancer - it will be as high as
60-80%. This high value can be used to justify relatively radical
preventive interventions such as preventive mastectomy. While it is
already difficult for BRCA mutation carriers to vote for preventive
mastectomy (this decision must be made at an early age, i.e. usually
below age 30), this decision seems even more difficult for women
whithout such a mutation. This is because in women without documented
mutation, it is much more difficult to assess the individual lifetime
risk. If no mutation is identified, family history data are used to help
predict the risk of being eventually diagnosed with breast cancer. With
the increasingly small number of family members in the western world, a
reliable "pedigree analysis" is, however, increasingly
difficult. Our data suggest that if MRI is done for screening, "secondary
prevention", i.e. intensified surveillance is efficacious to allow
an early detection of a possible breast cancer also in women without
mutation, and may be offered as a viable alternative to preventive
mastectomy.
Last, our cohort did also include women with only "moderately"
increased risk (lifetime risk of 20%). Until today, breast MRI had only
been suggested for screening women at high lifetime risk. According to
our data, even in the group of women at "only" moderatly
increased risk, MRI was the most accurate imaging modality, and still
offered a high PPV. This suggests that, if costs were no consideration,
MRI may prove useful for screening not
only "high risk women", but also those at "only"
moderately increased risk.
Bibliographical reference:
Christiane Kuhl
Section Oncologic Imaging, Department of Radiology, University of Bonn,
Bonn, Germany
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