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BREAST CANCER RISK AND PREVENTION
How can I determine how
high my risk of breast cancer is?
If my risk of developing
breast cancer is high as calculated by the Gail model or
other risk assessment tool, is there anything I can do
about it?
I have heard that Evista (raloxifene)
can also decrease my risk of getting breast cancer. Is
this true?
New Test Predicts Response to
Chemotherapy for Women with Early Breast Cancer.
FAMILY HISTORY
There is no one in my family
who has had breast cancer, so my chances of getting
breast cancer are very low aren't they?
My mother
had breast cancer.
Does that mean I will get breast cancer ?
Is there anything I can do to prevent from getting
breast cancer?
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Cancer Home Page
How can I determine how high my risk of breast cancer
is?
We can give an estimate of a woman's risk of developing
breast cancer based on several factors such as family
history, prior breast biopsy results, age at onset of
menstrual periods, etc. One popular "model" for
quantifying this risk is called the Gail model. By
"plugging in" all the pertinent information, a
calculation of the 5-year and lifetime risk can be
made. For the "no risk" women, her 5 year risk would be
about 1%, meaning that if there were 1000 women with no
risk factors, in five years, approximately 10 of them
would have developed breast cancer. A woman who has one
or more risk factors, such as family history, no
pregnancies, etc, her 5 year risk may be 1.5%, or 2.5%
or higher. This would mean that in a group of 1000
women with all those same risk factors, 15 or 20 would
develop cancer over the next five years.
You may want to look at a similar
risk calculation tool
at the National Cancer Institute website, where you
can do your own calculation.
Lifetime risk for a woman with no risk factors would be
in the range of 10%, meaning that 100 of 1000 similar
women would develop breast cancer sometime during their
lifetime. For women with one or more risk factors, their
lifetime risk may be 15% or perhaps as high as 50%.
If my risk of developing breast cancer is high as
calculated by the Gail model or other risk assessment
tool, is there anything I can do about it?
In 1998, a landmark study was published regarding the
use of tamoxifen in the prevention of breast
cancer. About 13,000 women were enrolled in this five
year trial, comparing tamoxifen to a placebo (sugar
pill). The incidence of breast cancer development over
about five years was decreased by about 50%. In the
placebo group, about 20 out of 1000 women developed
cancer, whereas only about 10 out of 1000 women
developed cancer in the tamoxifen group. These results
are dramatic, in that this the first ever drug study to
demonstrate the ability to prevent breast cancer from
developing in the first place.
If a women chooses to take tamoxifen for prevention, it
must be taken for a total of five years. One must be
aware that there are some potential undesirable side
effects. There were a few more cases of endometrial
cancer when taking tamoxifen, and there were more women
with blood clot problems. And there may be side effects
of hot flashes, vaginal discharge, cataract formation,
and depression. But for some women the benefits may
clearly outweigh the risks.
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I have heard that Evista (raloxifene) can also decrease
my risk of getting breast cancer. Is this true?
Raloxifene is a drug that was initially approved for the
prevention of osteoporosis. In the study which was
conducted to look at its effect in osteoporosis, it was
noted incidentally that there were fewer women diagnosed
with breast cancer when taking raloxifene.
On the basis of these findings, a large trial was
conducted a few years ago, including almost 20,000
women, which compared the use of Evista (raloxifene) to
tamoxifen for the prevention of breast cancer in women
who were at higher than average risk for developing
breast cancer. This was called the STAR trial
(Study of Tamoxifen and Raloxifene). The results
were published in 2006, and showed that Evista also
decreased the incidence of breast cancer over a 5 year
period. It is important to understand the size of the
benefit. These women had an average estimated risk of
about 4% for developing breast cancer over the next 5
years. This means that out of 100 women in the trial,
only 4 would be expected to be diagnosed with cancer in
5 years. But in the general population only 1 or 2 out
of 100 will develop cancer in 5 years, so the risk is
double or more. Now in the study, with 5 years of
either tamoxifen or Evista (raloxifene), only about 2
out of 100 women were diagnosed with breast cancer over
5 years, so the drugs both decreased the incidence of
cancer by half. While this is really good, the benefit
is limited to only 1 or 2 women out of 100 who take it,
at least over the first 5 years. It seems that the
higher one’s risk is, the more attractive these drugs
become as preventive treatment. You can find more
information at the
National Cancer Institute
website about this trial. Another
informative NCI site can be viewed
here.
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New Test Predicts Response to Chemotherapy for Women
with Early Breast Cancer.
The
diagnosis of breast cancer is a very frightening event
for any woman. It is accompanied by many fears and
anxieties, especially anxieties about the need for
chemotherapy, and the fear that the cancer will come
back. These concerns arise for many women despite that
fact that cancer is most often diagnosed in its early
stages, when the risk for recurrent disease is fairly
low. A new test is available that will help women
and their doctors in predicting their risk for
recurrence, and to determine if their cancer would
respond to chemotherapy.
The new test, called the OncotypeDX test, is
performed on tissue from the initial biopsy or
lumpectomy specimen. It uses the unique genetic
profile of each woman’s breast cancer to make an
accurate prediction about whether the cancer will
recur. It measures an array of genes that are known to
be associated with more aggressive tumors. The test has
been shown to be much more powerful than current
predictive methods, which are based on “clinical
staging”, which is based on the size of the tumor and
the status of the lymph nodes.
This OncotypeDX test has been studied in a large group
of women who had participated in two large national
breast cancer clinical trials through the National
Surgical Adjuvant Breast and Bowel Project (NSABP)
several years ago. All of these women had early stage
breast cancer at diagnosis, and all were treated in a
similar fashion, with tamoxifen. The OncotypeDX test
was performed on the initial tissue specimens for all
these women. The women were then grouped according to
the OncotypeDX test results.
All women had been followed for at least 10
years, so it was known who had recurrent cancer.
For the group as a whole, there were 15% who had
recurrence within the first ten years after diagnosis.
Using the OncotypeDX test, this group could be split
into 3 sub-groups, one whose recurrence risk was
extremely low, at 7%, a second group with an
intermediate risk, and a third group whose recurrence
risk was quite high, at 31%, despite being classified as
“early stage” by our current criteria. About half of
the women were in the low recurrence risk group. The
researchers concluded that the test is highly
prognostic for this group of breast cancer patients,
independent of treatment.
The test was also studied to see if it could predict
who would benefit from receiving chemotherapy.
Currently, many women with early stage breast cancer are
advised to receive chemotherapy, in a “one size fits
all” fashion, even though only a very small number are
actually going to benefit. Based on current clinical
staging, there is no simple way to decide which women
would not benefit from chemotherapy. In other
words, we overtreat many women with chemotherapy, for
lack of being able to distinguish which women will
actually benefit.
Using the OncotypeDX test, 50% of the women, all with a
low Recurrence Score, had no benefit from
receiving chemotherapy. Stated another way, if the
Recurrence Score is low, the risk of recurrence is
extremely low, and receiving chemotherapy makes no
difference in the outcome. On the other hand, in the
remaining 50% of women with an intermediate or high
recurrence score, there a much more dramatic benefit
from receiving chemotherapy, especially with a high
Recurrence Score. Incorporation of this test into the
decision process allows the doctor to individualize
treatment based on the “fingerprint” of the patient’s
cancer. Approximately 50% of women with early breast
cancer can thus avoid the toxicity that comes with
receiving chemotherapy.
This exciting new study was reported at the annual San
Antonio Breast Cancer Symposium held in December 2004
and subsequently published in the New England Journal of
Medicine. The test currently is only indicated for
patients with breast cancer that has not spread to the
lymph nodes, and also is “positive” for estrogen
receptors. The test is available for women at
DeKalb Medical Center. Most insurance companies cover
the cost of the test. It is expected that in the near
future the test will be validated in women with more
advanced breast cancer, potentially sparing additional
women the toxicity of chemotherapy. There is already
data showing that OncotypeDX is predictive of the
benefit of chemotherapy even in women with positive
lymph nodes, but its use in this setting is not yet
considered appropriate outside of research settings.
Use of the test may also eventually accelerate our
ability to identify unique molecular targets in breast
cancer, allowing for even greater precision and
individualization in treatment planning.
As the use of this test has expanded, there has been a
need to decide how best to treat those women who fall
into the “Intermediate” Recurrence Score group.
Currently, most oncologists would recommend chemotherapy
for many of these patients, though the data so far
appears to show no real difference in outcomes for women
whether they have chemotherapy or not. There is a
large national clinical trial underway to study this
further. It is called the TAILORx trial (Trial
Assigning IndividuaLized Options
for Treatment (Rx)). In this trial, women with a
low Recurrence Score are treated with hormonal therapy
only, and women with a high Recurrence Score are treated
with chemotherapy followed by hormonal therapy.
Patients with an Intermediate Recurrence Score are
randomized either to receive hormonal therapy alone, or
combined with chemotherapy. You can get more
information about this trial from the surgeons at DeKalb
Surgical, or you may visit this
NCI website for
more details.
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There is no one in
my family who has had breast cancer, so my chances of
getting breast cancer are very low aren't they?
Don't assume that you won't get breast cancer just
because it doesn't run in your family! Most breast
cancers are not inherited, meaning that any
female is at risk. If you have a lump in your breast,
or if you have a suspicious finding on your mammogram,
it must be evaluated carefully, regardless of whether
cancer runs in your family.
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My mother had breast cancer. Does that mean I will
get breast cancer?
If
someone in your immediate family has been diagnosed with
breast cancer, then your risk of developing breast
cancer is increased by about a factor of 2. If there
are more than one with breast cancer in your family,
your risk goes up further, especially if the cancers
occurred at a young age (younger than 40).
Although most breast cancers are not primarily due to
genetic factors (related to family history), there is a
group of women who carry a gene that carries with it an
extremely high risk for developing both breast and
ovarian cancer. These genes are called the BRCA1 and
BRCA2 genes. These gene mutations can be identified by a
blood test, but the cost is over $2000 currently. Most
women do not need to have this test done. But it is
usually recommended for women who have two or more young
family members with breast cancer, or if there is also a
family history of ovarian cancer. Each patient
considered for the test must be counseled about what the
test involves, and what ae the implications of the test
results. If you want more information, please contact
our office. The genetic testing and counseling is
available through the Kann Cancer Center at DeKalb
Medical Center.
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Is there anything I can do to prevent getting breast
cancer?
We
do know something about risk factors for breast cancer.
Breast cancer incidence is higher in patients who are
overweight, those who drink moderate to high amounts of
alcohol daily, and those who consume a diet high in
saturated fats. There is also a higher incidence in
those who have early onset of menstruation, those who
have no full-term pregnancies until late in life, or
those who never have any pregnancies. Also, for those
with children, breast feeding appears to decrease the
incidence of breast cancer.
Most women will not want to base their family planning
on decreasing their cancer risk, but it's at least
helpful to understand these potential implications. But
some basic preventive life styles make sense for most
everyone, namely, avoiding saturated fats as much as
possible, abstaining from alcohol, and maintaining an
ideal body weight. Other good life style measures in
general include complete abstinence form tobacco
products, a diet high in fiber, and a regular exercise
program.
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