Mayo Clinic: At my last mammogram, I asked my doctor if I
could be tested for the breast cancer gene. She didn’t think
it was necessary even though I have an aunt who had breast
cancer. How do doctors decide who should be tested? Why
shouldn’t all women be tested?
Genetic testing for the gene mutations associated with breast
cancer, called BRCA1 and BRCA2, is offered to people who are
likely to have inherited one of the mutations, based on their
personal and family medical history. There are other newer
genetic tests that may be available, too, depending on a
person’s family cancer history.
gene mutations are uncommon. Affecting only about one percent
of the population, they are responsible for approximately 5 to
10 percent of breast cancers. Because of their rarity, testing
everyone for them isn’t necessary or recommended. If you’re
concerned you might have one of these mutations, ask your
doctor to help you assess your overall risk.
first step in determining the possibility of a BRCA mutation
is gathering a comprehensive family history. Your doctor would
want to know if anyone in your family has had breast cancer or
other types of cancer. If you have a first-degree relative
with the disease — a parent, sibling or child — that has
more of an impact on your risk than other relatives who have
breast cancer, such as aunts or cousins. If you have a male
relative with breast cancer, that could raise your risk more
a relative was diagnosed with cancer also makes a difference.
People who have a BRCA gene mutation tend to develop breast
cancer at a younger age than people who do not. If someone in
your family had breast cancer before 50, that may increase the
possibility a genetic mutation could be involved.
a family with BRCA will show a pattern of breast cancer that
affects multiple family members over several generations
diagnosed with breast cancer at young ages. But other cancer
diagnoses should be reviewed, too. Ovarian, pancreatic or
prostate cancer at a young age also could point to a
hereditary predisposition to breast cancer.
family history suggests the possibility of a BRCA gene
mutation, consider meeting with a genetic counselor before you
make any decisions about testing. A genetic counselor can use
your family history to calculate the family’s risk of
hereditary breast cancer more specifically. He or she can help
you fully understand the pros and cons of genetic testing. A
genetic counselor also can offer guidance on the ideal
individuals in the family to be tested first.
genetic testing is recommended for you, you decide to have it
done, and you learn that you do have a BRCA gene mutation,
your risk for breast cancer would be much higher than normal.
In women without BRCA, the odds of getting breast cancer are 1
in 8. For people with a BRCA mutation, lifetime risk for
breast cancer ranges from 50 to 80 percent. With that in mind,
women who carry the mutation should be referred to a breast
health specialist or breast center to determine how often they
should be screened for breast cancer and review possible
medical and surgical treatment options that are available to
them, based on their individual circumstances.
mind that, for most people, the likelihood of having a BRCA
gene mutation is low — even when a family member has had
breast cancer. The vast majority of breast cancers are not
inherited. It is important, however, for all women to be
screened for breast cancer regularly. How often you need
breast cancer screening tests should be based on your personal
medical history, family history and preferences. Talk to your
doctor about the schedule that best fits your needs.