Home > Newsroom > Publications > Progress, Fall 2005
For Rosemary Buck and her daughters Carol
and Susan, finding out whether their cancers were genetically
related was motivated by more than curiosity. The threat of
a genetic link -- and another breast cancer diagnosis -- loomed
over the whole family. "After I was diagnosed, Susan decided
to undergo genetic testing," says Buck. "She wanted to know if
it was by chance or by genes that it struck all three of us.
I felt I needed to do it for the rest of the family," Weston
says.
Kara Milliron, M.S., C.G.C.
For families with a history of breast cancer, the availability
of genetic testing and counseling at major institutions like
the U-M Comprehensive Cancer Center offers much-needed guidance.Testing
can identify the presence or absence of mutations in two genes,BRCA-1
and BRCA-2 that can lead to the development of both breast
and ovarian cancers. "Only 1 in 300 to 1 in 800 people in
the general population carry the BRCA-1 or BRCA-2 mutation,"
says Kara Milliron, M.S., C.G.C., a certified genetic counselor
in the Cancer Center's Breast & Ovarian Cancer Risk Evaluation
Program. Statistically, about 20,000 women will be diagnosed
this year with breast cancer due to an inherited susceptibility.
Some of the predictors that may indicate an inherited susceptibility
to cancer in a family include:
- High numbers of family members with cancer through several generations, on either the mother or father's side.
- Family members diagnosed with cancer before age 50.
- Family members diagnosed with multiple cancers.
- Male breast cancers, or clusterings of certain other cancers.
One tablespoon of blood is all that's needed for the test, but,
as Milliron points out, "just because it's simple doesn't mean
it's easy. It's the emotional aspects of testing that make it
a challenge for families." That's why before any testing, an
in-depth counseling session takes place to assess family history and the
potential risk of having or
passing on the mutation.
Counselors like Milliron
discuss the risks, benefits
and limitations of testing.
During this phase, some
women may decide they
don't want to know whether
they carry the mutation. "That's okay," she says. "The right
to not know is just as important as the right to know."
Susan Weston's results did not indicate a genetic basis
for her cancer. Weighing other factors like the women's
age at diagnosis and the lack of other familial cancers,
the chances are extremely remote that the genetic defect
is present in any other family member. "That leaves us to
conclude that this was due to either pure chance, a rare
undetectable mutation in BRCA-1 and or BRCA-2 or
a mutation in some novel gene yet to be discovered,"
says Milliron.
Although it did not solve the mystery of why cancer
struck three times in Weston's family, genetic counseling
can provide unaffected family members with valuable
information. Personal risk assessments can be offered
which may suggest pursuing additional screenings or
chemoprevention.
Milliron confirms that breast cancer occurring in three
family members is extremely rare.But she's not surprised
that no mutation was found. "The majority of tests come
back negative," she explains. "Only 5 to 10 percent of breast
cancers can be attributed to inherited susceptibility."
To learn more about genetic counseling for breast and ovarian
cancer, visit the Breast & Ovarian Cancer Risk Evaluation Clinic's webpage or call the Cancer AnswerLine™ at 800-865-1125.
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