Studies
Show Progress in Breast Cancer Treatment
A
new genetic test could one day spare many women diagnosed with
breast cancer from the rigors of chemotherapy, according to
a report in the New England Journal of
Medicine.
The study of stored tissue samples
from 447 patients showed that the test, which looked at 16 cancer-related
genes, successfully identified women at very low risk of having
their cancer recur after treatment with tamoxifen, a standard
drug for the disease.
The
test is potentially applicable to about 50 percent of women
diagnosed with breast cancer, says Dr. Soonmyung Paik, director
of the division of pathology at the National Surgical Adjuvant
Breast and Bowel Project.
Tests
Useful in Certain Groups of Women
This
group includes women with cancers that are lymph-node-negative,
meaning the cancer has not spread past the breast, and receptor-positive,
meaning the tumor cells have receptors that make them grow when
exposed to the hormone estrogen.
The
study results indicate that half of those women, perhaps 25,000
each year, do not require the follow-up chemotherapy they now
get, Dr. Paik says.
The
test, which was developed with the help of the National
Cancer Institute (NCI), is commercially available now,
but is not widely used, he says. While the test "at this point
is very expensive," medical economic analyses indicate that
it might pay for itself through reduced treatment costs, says
Dr. Paik.
However,
another cancer expert says widespread use of the test should
await further studies of its effectiveness.
Dr.
Robert C. Bast Jr., co-author of an accompanying editorial in
the journal, is vice president for translational research at
the University of Texas M.D. Anderson Cancer Center. In this
role, Dr. Bast is responsible for bringing procedures
out of the lab into everyday practice.
One
reason why more trials are needed, Dr. Bast notes, is that none
of the women in the new study were treated with a new generation
of cancer drugs called aromatase inhibitors, which are starting
to displace tamoxifen, he explains.
In
fact, a study presented recently found the aromatase inhibitor
anastrozole was significantly more effective than tamoxifen
in increasing the number of women who remained free of cancer.
This lengthened the time before cancer recurred in many
patients and reduced the incidence of cancer spreading, particularly
to the other breast.
Dr.
Bast says another reason to wait for more research on the genetic
test is that the new study was "retrospective" - it looked back
at women who already had been treated with tamoxifen. Prospective
studies, which begin when women are diagnosed, are needed "to
confirm this finding in general," Dr. Bast remarks.
Dr.
Bast says he is not using the genetic test in his practice.
"I
would await confirmational studies," he says. "If they are as
strongly positive as this one, the test should go into wider
use."
Such
studies are being planned, says Sheila E. Taube, associate director
of the cancer diagnosis program at NCI.
"NCI
is working with clinical trials groups to develop a trial that
will in fact test the recurrence score prospectively," Taube
says. "The final design is not decided on yet, but it most likely
will focus on the group about which we need the most information,
women in the intermediate risk group."
Always
consult your physician for more information.
|
There
is good research news for women with breast cancer who carry
a cancer-causing gene and are treated with breast-conserving
therapy: the risk that cancer will recur in that breast is no
higher than for women who do not carry that gene.
But
the good news is balanced by a finding that the risk of cancer
in the opposite breast is increased significantly, says a report
in an upcoming issue of Cancer
by physicians at Memorial Sloan-Kettering Cancer Center in New
York City.
It
is a study done in the hopes of providing decision-making information
for women who carry one of the BRCA cancer genes and must choose
between mastectomy, removal of the entire breast, or lumpectomy,
removal of just the cancer and surrounding tissue, says study
author Dr. Mark Robson, an assistant attending physician at
Memorial Sloan-Kettering.
"It
has been a controversial issue," Dr. Robson notes. "Now we can
say that at least in the short and intermediate term - five
to 10 years - there is no greater risk of recurrence in that
breast than reported for other women."
The
study followed 87 women known to carry a BRCA gene who had lumpectomy
for a cancer in one breast. After 10 years, the cancer recurred
in 13.6 percent of those women, a rate comparable to that reported
for women who do not carry the gene.
More
than a third of the women - 37.6 percent - in the study had
a new cancer in the untreated breast within 10 years of their
original diagnosis, the study found. Dr. Robson says previous
studies have shown a rate of about 8 percent in women without
the gene.
The
decision about having lumpectomy or total breast removal, and
about having the unaffected breast removed because of the high
risk of cancer, must be made by the woman, Dr. Robson notes.
The study provides "another data point for women to use," he
says.
"Women
have to be made aware of their risks and the options for managing
those risks," Dr. Robson says. "This study can be used to help
understand those risks."
Overall,
about 5 percent of women with breast cancer are found to have
mutated BRCA genes that increase the risk of cancer, he said.
The incidence is higher in some ethnic groups, such as Jews
of Eastern European origin, Icelanders, the Dutch, and inhabitants
of the Balkans, Dr. Robson explains.
Several
studies about the risk of recurrence in those women have been
done, Dr. Robson says. "The results have been conflicting, but
most studies have been converging on the results that we obtained,"
he adds.
Whatever
the choice, these women should be monitored carefully, with
a magnetic resonance imaging or ultrasound screening test every
year, he says.
Always
consult your physician for more information. |
