In 1940, the lifetime risk (to age 85) of a woman developing
breast cancer in 1940 was 5%, or 1 in 20. Today, nearly 65 years
later, the risk is 12.6%, or 1 in 8. In women 40 to 49 years of
age, there is a 1 in 66 risk of developing breast cancer compared
with a 1 in 40 risk among women in the 50- to 59-year age group.
While these facts may sound disheartening, innovations in the
diagnosis and treatment of breast cancer offer hope for those
affected by this disease.
What are some advances in the diagnosis of breast
cancer?
While mammography is still the primary method for
diagnosing breast cancer, technologies such as magnetic resonance
imaging (MRI) and positron emission tomography (PET) scans are
finding some cancers missed by mammograms. In addition,
microcrarray technology shows promise for predicting the growth
potential of cancerous tumors.
What is magnetic resonance imaging?
Magnetic
resonance imaging (MRI) is a test that produces very clear
pictures, or images, of the human body without the use of X-rays.
MRI uses a large magnet, radio waves and a computer to produce
these images.
How is MRI used in diagnosing breast cancer?
MRI may
be used to distinguish between benign (non-cancerous) and malignant
lesions, which can reduce the need for breast biopsies. Although
MRI can detect tumors in dense breast tissue, it can't detect
microcalcifications (tiny specs of calcium), which account for
one-half of the cancers detected by mammography.
What is a PET scan?
A positron emission tomography
(PET) scan is a unique type of imaging test that helps doctors see
how the organs and tissues inside your body are actually
functioning.
The test involves injecting a very small dose of a radioactive
chemical, called a radiotracer, into the vein of your arm. The
tracer travels through the body and is absorbed by the organs and
tissues being studied. Next, you will be asked to lie down on a
flat examination table that is moved into the center of a PET
scanner. This machine detects and records the energy given off by
the tracer substance. With the aid of a computer, this energy is
converted into three-dimensional pictures. A physician can then
look at cross-sectional images of the body organ from any angle in
order to detect any functional problems.
How does a PET scan detect breast cancer?
Because
of their high rate of metabolism, cancer cells absorb high amounts
of the radioactive tracer. After the tracer is absorbed, PET scans
create an image of the breast, and the scan computes the rate at
which the tumor is using the tracer.