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Nearly 200,000 American women are
diagnosed with breast cancer each year, and between
5 percent to 10 percent of them have a heritable form
of the disease. Geneticists have identified mutations
on the BRCA1 and BRCA2 genes that predispose a person
to develop breast cancer. Women with alterations on
these genes have up to an 85% greater lifetime chance
of developing breast cancer than women with unaffected
genes. The mutations are also associated with an increased
risk of ovarian cancer. People of Ashkenazi Jewish descent
have a higher incidence of inheriting these mutations
than those in other ethnic groups. Although breast cancer
in men is far less common, a mutated BRCA2 gene, in
particular, increases their possibility of having the
disease. Furthermore, people with altered BRCA1 and
BRCA2 genes have a slightly greater risk to develop
cancer of the pancreas, stomach, or prostate than people
without the mutations.
Genetic testing for the mutated BRCA1 or BRCA2 genes
should be considered by those who have had ovarian cancer
at any age or breast cancer before they were 50 or have
relatives meeting the same parameters; people with family
histories of two or more cases of breast and/or ovarian
cancer; and males with breast cancer. The preferred
procedure is to first test a family member who has had
breast or ovarian cancer. If this is not possible, then
an at-risk family member can be tested directly.
A positive result indicates that the patient is at
higher risk for cancer. However, it cannot tell whether
cancer will actually occur, or when, or how aggressively.
That is why it is important to review test results with
an experienced genetic counselor. Some of the options
that can be considered in discussion with a genetic
counselor include:
Careful monitoring:
Increased frequency of mammograms and clinical breast
exams can help catch breast cancer at an earlier and
more treatable stage. Most importantly, is to begin
screening at-risk persons at an earlier age than is
recommended for the population at large.
For ovarian cancer, monitoring through transvaginal
ultrasound, CA-125 blood tests, and clinical exams can
sometimes find cancer at an early stage, but it is not
clear if these methods can reduce the risk of death
from ovarian cancer.
Prophyltactic Surgery:
Removal of the breasts (mastectomy), ovaries and fallopian
tubes (salpingo-oophorectomy), or both the breasts and
the ovaries can reduce (but not eliminate) the risks
of developing breast or ovarian cancer. A Salpingo-
oophorectomy may be recommended for women past childbearing
age, as ovarian cancer is difficult to detect in its
early stages. The younger the patient with altered genes
is when she has a preventive mastectomy, the greater
the potential benefit. Surgery is a particularly complex
and highly personal option to consider and is best made
by the patient with information by her physician and
her genetic counselor and the support of her family.
Chemoprevention:
In general, tamoxifen has been found to be effective
in reducing the risk of developing cancer and in reducing
the chance that cancer will reoccur in women at increased
risk for developing the disease.
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