ó After breast cancer tumors are removed, many women undergo
chemotherapy to eradicate any remaining cancer cells and
reduce the risk that the disease will recur. The drugs can
make them nauseous and anxious and lead to hair loss.
blood test under development at the Johns Hopkins University
could reduce the number of women who need chemotherapy
significantly by revealing who has residual cancer cells after
surgery to remove the tumors.
are over-treating breast cancer because they donít know who
to treat" after surgery, said Dr. Ben Ho Park, a Hopkins
associate professor of oncology working on the test.
"Wouldnít it be great if we could tell patients theyíre
actually free of their cancer?"
one of many avenues researchers are following in the hunt for
simple, useful blood tests for breast cancer, the most common
kind for women after skin cancer, according to the U.S.
Centers for Disease Control and Prevention. Every year more
than 200,000 women are diagnosed and 40,000 die.
tests remain many years away, if they ever become commercially
available. Eventually they may be able not only to reliably
predict if breast cancer is likely to return, but to diagnose
the disease before there are symptoms and track the
effectiveness of treatment.
testing now isnít so simple. Just to differentiate the type
of breast cancer a patient has, for example, surgeons must
examine a small piece of the tumor under a microscope.
test widely used now only identifies the small number of women
with inherited gene mutations that increase the risk of
eventually developing breast cancer. There are some blood
tests to show if cancer has recurred, but they are often
test seeks to identify with certainty the 30 percent of
early-stage breast cancer patients who will have a recurrence
so they can get additional therapies such as chemotherapy,
while those not expected to get the disease again can be
spared the toxic and expensive treatment.
would look for DNA molecules that cancer cells shed into the
blood. In early trials, the test was able to tell the
difference between these cancerous DNA molecules and normal
ones. Now a larger trial at several medical centers is
said the test could be easy, quick and cheap to perform in a
lab ó eventually.
lot of companies may jump the gun and begin offering blood
tests, but itís still all research," Park said.
"We need to prove this is as good as we think it
Thompson said making treatment decisions without knowing her
chances of recurrence was among the toughest parts of her
breast cancer diagnosis nine years ago.
researcher fairly new to Baltimore, the Phoenix mother of four
was shocked during her first mammogram at 40 to learn she had
a tumor. She was told twice she probably didnít need
chemotherapy; then another small invasive tumor was spotted
that could have been trouble.
estimated she had a 20 percent chance of cancer returning
after surgery, 10 percent with chemotherapy and 5 percent if
she also took a drug that was still fairly new called
Herceptin that targeted specific proteins in cell membranes.
scary to make decisions without all of the information you
would like," Thompson said. "As a young person with
young children, your knee-jerk reaction is to be as aggressive
Thompson decided on both treatments, though her doctor told
her a young patient had just died after taking the Herceptin,
a pill Thompson would need to take for a year. The weeks of
chemotherapy meant hours at a time in a chair with an IV in
her arm, hair loss and increasing fatigue and nausea.
decided on a bilateral mastectomy to prevent a recurrence or a
new cancer, though research shows no better outcomes.
years later, she is cancer-free, but she doesnít know if she
actually prevented a recurrence. She discusses her decisions
routinely now that she has become a nurse navigator at Hopkinsí
LiveWell Center for young women with breast cancer.
someone was able to say I could have definitely skipped chemo,
I would have been delighted," she said. "Or that the
Herceptin wasnít necessary? Weíre just not there
with certainty which treatments would help which patients
would be a huge advance, said Dr. Eric P. Winer, director of
breast oncology in the Susan F. Smith Center for Womenís
Cancers at Dana-Farber Cancer Institute in Boston and a
spokesperson for the American Association for Cancer Research.
cancer is a set of diseases, he said, and generally doctors
know the most advanced treatments for some kinds are
ineffective for others.
example, aromatase inhibitors, developed by a University of
Maryland researcher, lower levels of the hormone estrogen that
fuels tumors in some breast cancer. But they donít work on
breast cancer lacking estrogen receptors.
said other new tests could show specific gene defects to
target, or if there are no good targets, which is the case in
some breast cancers and some recurrent, or metastatic,
need to develop predictive tests that tell us who will benefit
and who would not, so we donít waste drugs and
dollars," he said. "We need to target (therapies) to
people who will benefit most."
a goal of the National Cancer Instituteís Cancer Diagnosis
Program, which funds research in labs at Dana-Farber, as well
as Hopkins and the University of Maryland and other cancer
is to find new, targeted drugs, including for the minority of
cases that are so-called triple negative, which donít
respond to hormonal or other new treatments, said Tracy G.
Lively, associate chief of the programís Diagnostics
program funds research based on its promise and feasibility.
She said early detection tests would be the hardest to develop
because the DNA shed by small new tumors would be diluted in
large volumes of blood. Tests would need to be what
researchers call "sensitive and specific," or
reliably able to identify those with the disease and those
blood tests to track the effectiveness of treatment and
disease recurrence would be less difficult, she said, because
doctors would know what they were looking for after breast
cancer is confirmed.
are really pressing ahead on all of these fronts," Lively
said. "But everything has to be tested. It may seem like
it has promise, but it might be disappointing."
the challenges, the search continues for a variety of blood
tests, including diagnostic ones.
primary method of testing for breast cancer now is the
mammogram, imaging that is uncomfortable and sometimes
inconclusive. That leads to more tests to confirm or rule out
disease, potentially causing unwarranted alarm in patients.
test under development at the University of Maryland likely
wouldnít replace mammograms but could augment them or allow
less frequent imaging. The test looks for a certain protein
called GP88 that is associated with estrogen-receptor positive
breast cancer, the most common type.
studies suggest GP88 can predict who will have a disease
recurrence, said Dr. Katherine Tkaczuk, professor of medicine
and head of the breast evaluation and treatment program at
Marylandís Greenebaum Cancer Center.
and partners at Columbia-based A&G Pharmaceutical Inc. are
launching a trial to see if it can be used to help diagnose
early breast cancer just by its existence in a patientís
will test 700 women with no history of breast cancer at the
time of their annual mammograms. If the test reliably detects
cancer, it could more easily and less expensively screen large
groups of women with no access to imaging.
could also aid women whose images werenít clear because of
dense breasts or another condition, or who avoided the test
because of discomfort or inconvenience. Or women in general
may be able to have mammograms less frequently, Tkaczuk said.
test has potential, if itís sensitive and specific
enough," she said. "For certain patients, maybe it
wouldnít be used exclusively, but maybe every other year. Or
you go for a screening mammogram only if the test finds
something abnormal. I think a lot of women would welcome