The American Cancer Society recently recommended
MRI screening in addition to mammography screening
in women aged 30 and over who are at a high risk for
developing breast cancer. A recently completed study
also indicated that MRI screening of the opposite breast
in women newly diagnosed with breast cancer will find
about 3% of cancers that were missed on mammography.
No mention was made of the use of breast ultrasound as
an additional screening tool in a dense breast. Actually,
in experienced hands with a negative mammogram and a negative
ultrasound, there is a less than 1% chance of missing a cancer
(false negative rate). This is the same false negative
rate as a negative MRI!
The advantage of mammography and ultrasound together in dense breasts
is that there are fewer unnecessary biopsies, it is significantly less
expensive and, I think more user friendly for the patient. Experienced
radiologists have been performing mammography and breast ultrasound a lot
longer than breast MRI and we know what we need to biopsy and what we can
safely not worry about. We have statistics accumulated
over many years to back us up.
The biggest disadvantage of screening breast ultrasound is that it is
very consuming of the radiologist's time and therefore not available
everywhere and it does not find noninvasive breast cancer (Ductal Carcinoma In Situ).
It also does not add additional information in fatty replaced breast tissue.
A lot of insurances do not reimburse for screening ultrasound.
In high risk young women with dense breasts, MRI will find a significant
number of additional cancers, but remember, so will ultrasound. I feel
strongly that screening with MRI should be recommended with knowledge of
family history, available genetic information, the appearance of the breast
on the mammogram and pertinent medical history
(previous radiation to chest area, for example).
Most importantly, breast MRI is extremely dependant on dedicated breast
coils (which most MRI centers do not have) and I think even more
importantly on meticulous attention to technique. MRIs can look totally
normal because they were not performed correctly!
As a radiologist specializing in breast imaging, my biggest concern is
that there will be a rush towards screening with MRI in centers that are
not qualified to perform it. Even excellent radiologists will be totally
fooled by a poorly performed MRI of the breast. As of now, there is no
policing of MRI centers performing breast MRIs, such as is in place for
mammography, and this will lead to huge expense, unnecessary anxiety and
biopsies, a false sense of security for the patient and little additional
accurate information.
