Read
the Feb. 4, 2007 article from U.S. News and World
Report, "Density Danger" to
learn more about breast density.
BREAST
CANCER SCREENING and BREAST DENSITY Q & A:
Why
is breast density significant?
Dense breasts
contain more glandular and connective tissue. Less dense
breasts are mainly made up of fat tissue. Every woman has
different amounts of the different types of tissue in her
breasts. Breast cancer itself is made up of dense tissue.
This means that on a mammogram, a tumor is harder to spot
in dense tissue than in fatty tissue, because the tumor
looks a lot like the tissue around it. An analogy is often
used to describe the way dense tissue looks on film, "It's
like looking for a polar bear in a snow storm." Breast
cancers are readily seen in fatty tissue with up to 98%
sensitivity in film mammography.
Dense breast tissue itself is a risk factor for breast
cancer, with the risk 4-6 fold higher in women with
extremely dense breasts compared to fatty breasts, and
breast cancer is more likely to develop in denser areas of
the breast. Extremely dense (>75% dense) or
heterogeneously dense (51-75% dense) is present
in over half of women younger than age 50 years and
one-third of women age 50 years and
older.
How
often is cancer missed using standard film mammography, in
women with dense breasts?
With
film mammography, only 30-55% of breast cancers are
detected in women with dense breasts.
What is the prevalence of dense breast tissue in
women?
According
to the American College of Radiology Imaging Network
(ACRIN), 40% of all women undergoing screening mammography
have dense breasts. Breasts tend to become less dense as
women get older, but some women continue to have dense
breast tissue throughout life.
How
do you know if you have dense breasts?
Only
a mammogram can tell you for sure. Look for the terms
"heterogeneously dense or very dense", or "extremely dense"
in your mammogram report, which would indicate dense
breasts.
I
have dense breasts; what do I do differently, if
anything?
It
depends on what you are doing now, but these are important
factors to consider in addition to nationally recommended
guidelines:
• Be
diligent with recommended monthly self breast exams and
yearly mammography and clinical exams.
• DO NOT skip a year with your annual mammogram. Have
prior exams sent to your current facility. This will allow
small changes to be seen. This is difficult if the previous
year's film is not available.
• Go to a facility which specializes in breast imaging
• Go to a facility with digital mammography, when
possible, if you fit the guidelines (see below).
• Follow up any suspicious, palpable lump with further
imaging.
• See a breast surgeon or surgeon specializing in this
area to follow up on suspicious areas, when unsure.
• Trust your intuition
• Ask for whole breast ultrasound screening if it is
offered at your facility and they have the equipment and
the expertise to do it.
What
is important about digital mammography and where can I have
it done?
In
a recent study with nearly 50,000 women participating, they
found that digital mammography was more sensitive than film
in finding cancers in women with dense breasts. Sensitivity
for women with dense breasts was only 55% for film and 70%
for digital, though these are in the most perfect research
conditions. Digital mammography allows the radiologist to
see images more clearly and to manipulate the image to see
it better (brightness, contrast, size, and orientation).
Digital mammography is not widely available and is very
expensive for the facility. If you aren't sure what
facilities have it in your area, ask your physician to be
sure. Because of it's popularity, you may need to request
it specifically at your imaging facility. Until it is more
widely available, choosing a facility with specialization
in breast imaging is the most important
factor.
Did the study say who would benefit most from digital
mammography?
Yes. Digital
mammography was significantly better in screening women who
fit any of these three categories:
• Under age 50 (no matter density)
• Any age with heterogeneously (very dense) or
extremely dense breasts
• Pre- or perimenopausal women of any age (defined as
having last menstrual period within 12 months of mammogram)
There
was no benefit for women who fit ALL the following
categories:
• Over age 50
• Don’t have dense breasts
• Not menstruating
How is ultrasound important?
Ultrasound can
be used to evaluate masses that are hard to see on a
mammogram. Especially for women with dense breasts,
ultrasound is helpful in characterizing lumps or other
areas of concern. Ultrasound may also play an important
role in early detection (screening) women with dense
breasts, though further studies are ongoing.
How
effective is it?
Ultrasound
has proven to increase the number of cancers detected by
67-100% in studies at single institutions. In addition,
smaller invasive cancers have been found with this
technology, usually before the cancer has spread to the
lymph nodes.
Why isn't that done all the time, instead of mammography?
Mammograms are
still important for women with dense breasts because they
are good at showing calcifications which are sometimes
produced by early breast cancers.
Ultrasound is used to diagnostically evaluate areas of
concern, right now. Screening ultrasound looks at the
entire breast the way screening mammography does now. The
use of screening ultrasound in high risk women is under
investigation with the AVON/ACRIN 6666 trial with Dr.
Wendie Berg as the Principal Investigator.
Until then, about a third of U.S. facilities offer
screening ultrasound, so it is reasonable to request it, if
offered by your breast imaging facility (if they have good
equipment and the expertise to do it).
With any test,
there is a risk of finding something that needs to be
biopsied but is not due to cancer. You may want to check
whether your insurance covers screening ultrasound. The
first results of the AVON/ACRIN 6666 trial will be
announced in mid to late 2007.
Other
Breast Cancer Facts:
•
Approximately 211,000 new diagnoses of breast cancer each
year
• Approximately 58,00 new diagnoses of non-invasive
each year
• 40,000 women will die this year of breast cancer-one
every 13 minutes in the U.S.
• Every 2 minutes someone is diagnosed
• Majority of breast cancers occur in women over 50,
but women at any age can have breast
cancer
The
number
one risk factor for breast cancer is BEING A
WOMAN, the second is
GETTING OLDER!
Seventy
per cent of the time there are no identifiable risk
factors when a woman is
diagnosed. You can reduce your risk for disease and improve
the quality of your life, but there are no guarantees, or
fool-proof formulas for preventing
disease.
A
special thanks to Wendie Berg, MD, PhD, FACR, Breast
Imaging Consultant and Study Chair for the
American College of Radiology Imaging Network
(ACRIN) Protocol on Screening Breast
Ultrasound, for reviewing the material presented for
content and accuracy