BREAST CANCER SCREENING and BREAST DENSITY Q & A:
Learn more in Pam's recently published book,
You Should Know About Breast Cancer.
is breast density significant?
Dense breasts contain more glandular and connective tissue
than do fatty breasts. Every woman has different amounts of
the different types of tissue in her breasts. Breast cancer
itself is dense. 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 finding cancer in dense
breast tissue that "it's like looking for a polar bear in a
snowstorm." Breast cancers are readily seen in fatty tissue
with up to 98% sensitivity on mammography.
Dense breast tissue itself is also 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
How do you know if you have dense
The mammogram is the usual way to know the breast density,
though CT and MRI also can show it. You and your doctor
cannot tell how dense your breasts are by the way they
Most mammography reports use the following terminology to
categorize and describe breast density using four different
categories: (A) mostly fatty; (B) scattered fibroglandular
tissue; (C) heterogeneously dense; and (D) extremely dense.
The BI-RADS classifications (American College of Radiology
Breast Imaging Reporting and Data System) are used as a
part of a radiologist's mammographic report. Look for the
terms "heterogeneously dense", or "extremely dense" in your
mammogram report or letter of your mammography results,
which would indicate dense breasts.
often is cancer missed using standard mammography in women
with dense breasts?
With mammography, fewer than half of breast cancers present
are detected in women with dense breasts. Despite its
limitations, mammography is still an important piece of
early detection. Please read more below.
dense breast tissue normal?
Yes. About 40% of all women undergoing screening
mammography have dense breasts. Breasts tend to become less
dense as women go through menopause, but some women
continue to have dense breast tissue throughout life.
Extremely dense or heterogeneously dense tissue is present
in over half of women younger than age 50 years and
one-third of women age 50 years and older.
have dense breasts; what do I do differently, if
It depends on what you are doing now, but these are
important factors to consider in addition to nationally
• 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 help
allow small changes to be seen. This is difficult if the
previous mammograms are not available.
• Go to a facility which specializes in breast
imaging, when possible, to make sure you have experts who
spend most of their time in this area.
• Go to a facility with digital mammography, when
possible, if you fit the guidelines (see below).
• Make sure you talk to your doctor about following 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
•If you have a family history or other risk factors,
ask your doctor or your radiologist if you may qualify for
supplemental screening with MRI.
• If you do not qualify for MRI, ask for whole breast
ultrasound screening if it is offered at your facility and
they have the equipment and the expertise to do it.
is important about digital mammography and where can I have
In the D-MIST study with nearly 50,000 women participating,
digital mammography was more sensitive than film
mammography in finding cancers in women with dense breasts.
Sensitivity for women with dense breasts was 55% for film
and 70% for digital, though these results were in 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 widely available.
Did the study say who would benefit most from digital
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
• Over age 50
• Don’t have dense breasts
• Not menstruating
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. The Avon/ACRIN 6666 Trial showed
that when added to a screening mammogram, among women who
were at increased risk of breast cancer and had dense
breast tissue, ultrasound increased cancer detection.
effective is ultrasound?
Mammography alone finds about 5 cancers per 1000 women
screened. When ultrasound is performed in women with dense
breasts, another 3 cancers per 1000 women screened are seen
only by ultrasound.. The cancers seen only with ultrasound
are mostly small invasive cancers that have not yet spread
to the lymph nodes. For women at high risk for breast
cancer who are not able to have MRI, ultrasound improves
detection of breast cancer over mammography alone. MRI is
more sensitive and better for those at high risk, but is
costly and insurance may not pay for it. Ultrasound is less
costly, doesn’t involve radiation, and may be easier
for many women to tolerate and obtain. Breast MRI’s
involve IV contrast being injected into the veins, and the
usual examination requires lying still in a tunnel for
30-60 minutes, though a few centers are starting to offer
“fast” MRI that takes less than 10 minutes.
Why isn't ultrasound or MRI screening used instead of
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 often used diagnostically to evaluate areas
of concern seen on mammography or to check clinically
concerning findings. Screening ultrasound looks at the
entire breast, but is not routine in many clinics. Most
technologists are not trained in whole breast ultrasound
screening and when done, it can be a lengthy process.
Technologists are mostly trained in diagnostic ultrasound
screening, where they are looking at a single area of
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
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).
about 3D mammography?
Tomosynthesis, or 3D mammography is yet another tool in the
arsenal of a woman with dense breasts. Read
HERE to learn more
from www.densebreast-info.org .
Tomosynthesis (3D mammography), ultrasound, and MRI have
all been proven to increase the detection of cancer beyond
that of digital mammography, with more cancers seen using
MRI than ultrasound and more with ultrasound than
tomosynthesis, though more comparative studies are needed.
The cancers seen only with ultrasound are mostly small
invasive cancers which have not yet spread to the lymph
nodes; MRI also sees some cancers that are still confined
within the ducts (ductal carcinoma in situ) which cannot
spread beyond the breast. In most centers you must have an
identified area of concern before ultrasound would be done;
hence the need for SBE, CBE, and RAM (regular, annual
mammograms), to identify areas of concern so further
imaging can be done (often with ultrasound). MRI is usually
only offered to women who meet high-risk criteria. If
tomosynthesis is available, it can show areas of distortion
(like a tugging at the fabric of the breast) due to breast
cancer that might not show up on a standard digital
mammogram, but cancers in dense breasts are not always seen
• Approximately 211,000 new diagnoses of breast cancer
• Approximately 58,000 new diagnoses of non-invasive
breast cancer (ductal carcinoma in situ, DCIS) 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
WOMAN, the second
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.
Learn steps to take for early detection of cancer.
thanks to Wendie Berg, MD, PhD, FACR, Professor of
Radiology, Magee-Womens Hospital of UPMC and the University
of Pittsburgh School of Medicine, for reviewing the
material presented for content and accuracy.
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