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Reading a
Mammogram The mammogram is first checked by the technologist
and then read by a diagnostic radiologist,
a doctor who specializes in interpreting x-rays. The
radiologist looks for unusual shadows, masses, distortions, special patterns
 of
tissue density, and differences between the two breasts (see photo).
The shape of a mass can be important, too. A growth that is benign
(noncancerous) such as a cyst, looks smooth and round and has a clearly
defined edge. Breast cancer, in contrast, often has an irregular outline
with finger-like extensions.
Many mammograms show nontransparent white specks. These are calcium deposits
known as calcifications.
 Macrocalcifications
are usually associated with benign breast conditions; many clusters of
macrocalcifications in one area may be an early sign of breast cancer.
Microcalcifications are
tiny flecks of calcium found in an area of rapidly dividing cells. Clusters
of numerous microcalcifications in one area can be a sign of ductal carcinoma
in situ. (See DCIS, page 8.) About half of the cancers found by mammography
are detected as clusters of microcalcifications.
Reporting the
Results The radiologist will report the findings from your
mammogram directly to you or to your doctor, who will contact you with
the results. If you need further tests or exams, your doctor will let
you know. If you don't get a report, you should call and ask for the
results.
~ Don't simply assume
that the mammogram is normal
if you do not receive the results. ~
Your mammograms are an important part of your health history. Being
able to compare earlier mammograms with new ones helps your doctor
evaluate areas that look suspicious. If you move, ask your radiologist
for your films and hand-carry them to your new physician, so they can be
kept with your file. Always make sure that the radiologist who reads
your mammogram has the old films to use for comparison.
Mammograms
and Breast Implants A woman who has had breast
implants should continue to have mammograms. (A woman who has
had an implant following breast cancer surgery should ask her doctor whether
a mammogram is still necessary.) However, the woman should inform the
technologist and radiologist beforehand and make sure they are experienced
in x-raying patients with breast implants.
Because silicone implants are not transparent on x-ray, they can
block a clear view of the tissues behind them. This is especially true
if the implant has been placed in front of, rather than beneath, the
chest muscles.
Experienced technologists and radiologists know how to carefully
compress the breasts to avoid rupturing the implant. They can also use
special techniques to detect abnormalities, sliding the implant backward
against the chest wall, and pulling the breast tissue over and in front
of it. Interpreting the mammogram can also be difficult, especially if
scar tissue has formed around the implant or if silicone has leaked into
nearby breast tissues.
Choose a Mammography Facility
Many places--breast clinics, radiology departments of hospitals, mobile
vans, private radiology practices, doctors' offices--offer high-quality
mammography. Your doctor can arrange for a mammogram for you, or you can
schedule the appointment yourself. You can call NCI's Cancer Information
Service (1-800-4-CANCER) to find a mammography facility in your
community.
All facilities must be certified by the Food and Drug Administration
(FDA). (See Assuring High-Quality Mammography, page 13.) Staff of the
facility are required to post the FDA certificate in a prominent place;
if you don't see it, you should ask about certification. Without the FDA
"seal of approval," it is now illegal for mammographic
facilities to operate.
SIDEBAR:
Assuring High-Quality Mammography
In addition to quality, another important consideration is cost. Most
screening mammograms cost between $50 and $150. Most states now have
laws requiring health insurance companies to reimburse all or part of
the cost of screening mammograms; check with your insurance company.
Medicare pays some of the cost for screening mammograms; check with your
health care provider or call the Medicare Hotline (1-800-638-6833) for
details.
Some health service agencies and some employers provide mammograms
free or at low cost. Low cost does not mean low quality, however. A
large government survey found that some of the facilities charging the
lowest fees (often because they serve large numbers of women) were among
the best in terms of complying with high-quality standards.
Your doctor, local health department, clinic, or chapter of the
American Cancer Society, as well as NCI's Cancer Information Service at
1-800-4-CANCER (1-800-422-6237), may be able to direct you to low-cost
programs in your area.
Schedule a Regular Mammogram
Early detection of breast cancer is crucial for successful treatment,
and regular screening mammography is currently the best tool for early
detection. A 1993 survey by the National Center for Health Statistics
found that 60 percent of all women ages 40 to 49 got a mammogram in the
preceding 2 years, and 65 percent of women ages 50 to 64 had done so,
but only 54 percent of women ages 65
and over had been screened during that time. It is clear that many women
still do not get mammograms at regular intervals. Sadly, the women least
likely to have regular exams include those at highest risk, women ages
60 and older.
The reason women most frequently give for having--or not
having--a mammogram is whether or not the doctor suggested it. Although
surveys show that more doctors routinely advise women about mammography,
some fail to do so--because they forget, or because they assume that
another doctor has done so. If your doctor doesn't suggest mammography,
it will be up to you to raise the issue.
Other Techniques
for Detecting Breast Cancer
Clinical Breast Exam
Most professional medical organizations recommend that a woman have
periodic breast exams by a doctor or nurse along with getting regular
screening mammograms. You may find it convenient to schedule a breast
exam during your routine physical.
The examiner will look at your breasts while you are sitting and while
you are lying down. You may be asked to raise your arms over your head
or let them hang by your sides, or to press your hands against your hips.
The examiner checks your breasts carefully for changes in the skin such
as dimpling, scaling, or puckering; any discharge from the nipples; or
any difference in appearance between the two breasts, including differences
in size or shape. The next step is palpation:
Using the pads of the fingers to feel for lumps, the examiner will systematically
inspect the entire breast, the underarm, and the collarbone area, first
on one side, then on the other.
A lump is generally the size of a pea before a skilled examiner can
detect it. Lumps that are soft, round, and smooth tend not to be
cancerous. An irregular, hard lump that feels firmly anchored within the
breast tissue is more likely to be a cancer. However, these are general
observations, not hard and fast rules.
~ The only sure way to
know if a solid lump
is cancer is to have some tissue removed
and examined under the microscope. ~
A breast exam by a doctor or nurse can find some cancers missed by
mammography, even very small ones. In addition to the skill and
carefulness of the examiner, the success of a physical exam can be
influenced by your monthly cycle and by the size of your breast, as well
as by the size and location of the lump itself. Lumps are harder to find
in a large breast.
Currently, mammography and breast exams by the doctor or nurse are
the most common and useful techniques for finding breast cancer early.
Other methods such as ultrasound may be helpful in clarifying the
diagnosis for women who have suspicious breast changes. However, no
other procedure has yet proven to be more effective than mammography for
screening women with no symptoms; thus, most alternative methods of
breast cancer detection are used primarily in medical research programs.
Ultrasound
Ultrasound works by sending high-frequency sound waves into the breast.
The pattern of echoes from these sound waves is converted into an image
(sonogram) of the breast's
interior. Ultrasound, which is painless and harmless, can distinguish
between tumors that are solid and cysts, which are filled with fluid.
Sonograms of the breast can also help radiologists to evaluate some lumps
that can be felt but are hard to see on a mammogram, especially in the
dense breasts of young women. Unlike mammography, ultrasound cannot detect
the microcalcifications that sometimes indicate cancer, nor does it pick
up small tumors.
CT Scanning
Computed tomography,
or CT scanning, uses a
computer to organize and stack the information from multiple x-ray, cross-sectional
views of a body's organ or area. The scans are made by having the source
of an x-ray beam rotate around the patient. X-rays passing through the
body are detected by sensors that pass the information to
computers. Once processed, the information is displayed as an image on a
video screen. CT can separate overlapping structures precisely and is
sometimes helpful in locating breast abnormalities that are difficult to
pinpoint with mammography or ultrasound--for instance, a tumor that is
so close to the chest wall that it shows up in only one mammographic
view.
Research on New
Techniques
Several new techniques for imaging the breast are in the research stage.
These include the use of magnetic
resonance imaging (MRI) and positron
emission tomography (PET scanning) to identify tissues that are
abnormally active. MRI uses a large magnet to surround the patient along
with radio frequencies and a computer to produce its images. PET scanning
uses signals from radioactive traces to construct images. Laser
beam scanning shines a powerful laser beam through the breast,
while a special camera on the far side of the breast records the image.
Researchers are also striving to improve the detection power and diagnostic
accuracy of mammography. Digital
mammography is a technique for recording x-ray images in computer
code, improving the detection of breast abnormalities. Computer-aided
diagnosis, or CAD,
uses special computer programs to scan mammographic images and alert radiologists
to areas that look suspicious.
Finally, medical researchers are exploring the use of biological
tests to detect tumor markers for breast cancer in blood, urine, or
nipple aspirates.
Gene Testing
for Breast Cancer Susceptibility A breast cell progresses from
normal to cancerous through a series of several distinct changes, each
one controlled by a different gene or set of genes. Researchers have precisely
located the BRCA1 and
BRCA2 genes, key regions
within a woman's chromosomes
that control cell growth in breast tissue. A woman can inherit a mutation,
an alteration in these genes that are essential for normal growth of breast
cells, and this inherited change may put her at greater risk for eventually
developing breast cancer. The recent identification of genetic
changes in BRCA1 and BRCA2 makes a gene test possible.
 Scientists
estimate that alterations in the BRCA1 and BRCA2 genes may be responsible
for about 5 to 10 percent of all the cases of breast cancer and for about
25 percent of the cases in women under the age of 30. BRCA1 mutation testing
is primarily done in certain families whose members are inclined to develop
breast cancer at an early age because of an inherited change. Special
counseling programs occur before and after the testing to inform women
about the possible consequences of receiving test results. It is hoped
that these genetic tests may one day enable scientists to delay or prevent
breast cancer in high-risk families. Positive results may enable careful
watchfulness when appropriate; negative results may reassure those women
in high-risk families who are at no greater than average risk for breast
cancer.
Scientists at NCI and elsewhere believe that tests for alterations in
genes that control growth in breast tissue and in other genes throughout
the body require careful study to establish their appropriate use. In
addition to BRCA1 and BRCA2, other genes and the proteins they control
may be involved in breast cancer, and much more needs to be learned
about the risk associated with particular genetic alterations. NCI
supports research on the development of new genetic tests offered within
a research setting and accompanied by genetic counseling. Counseling is
important because test results must be properly understood, and a
counselor can help persons with a positive test to handle possible
discrimination in health or life insurance or in the workplace.
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