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 narrowing the diagnosis for women who have suspicious
breast changes. However, no other method is yet effective for
screening women with no symptoms, and most of them are used
primarily in research programs.
works by sending high-frequency sound waves
into the breast. The pattern of echoes from these sound waves is
converted into an image, called a sonogram, of the breast's
interior. Ultrasound, which is painless and harmless, is especially
good in distinguishing between tumors, which are solid, and cysts,
which are filled with fluid. Sonograms of the breast can also be
helpful in evaluating some lumps that can be felt but are hard to
see on mammography, 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.
Computed tomography, or CT scanning,
uses a computer to
organize the information from multiple x-ray views and constructs a
cross-sectional image of the body. CT is sometimes helpful in
locating breast lesions 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.
Several even newer techniques for imaging the breast are in the
research stage. These include
Magnetic Resonance Imaging
MRI, which relies on magnetic fields and radio waves to produce a
likeness of body tissues, and
Positron Emission Tomography (PET
, which can identify tissues that are abnormally
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.
Research is also under way to develop laboratory tests that
could be used to detect cancer in blood samples.
are substances produced either by tumors or by the body
in response to tumors. Elevated blood levels of certain biomarkers
can be helpful in confirming a diagnosis or watching for tumor
recurrence. However, because most biomarkers can be elevated even
in some healthy people, they are not yet practical for screening
for breast cancer.
Someday it may be possible to identify
that predispose women to breast cancer. At present, this type of
testing is limited to certain rare families whose members are
inclined to develop breast cancer at an early age and who have
cells that carry an inherited genetic mutation.