-
Source: ONE News
Chemotherapy helps improve breast cancer survival in
post-menopausal women, adding to a long-standing debate about how
best to treat these women, US researchers said.
A gene-based test called Oncotype DX made by Genomic Health Inc may
help identify a small group of women who are not likely to benefit
from chemotherapy, a second study found.
The main study proves that adding chemotherapy to treatment with
the oestrogen-blocking drug tamoxifen can help prevent cancer from
coming back in women with oestrogen-receptor positive breast
cancers, the most common kind in which a hormone is driving the
cancer.
"We have a survival benefit that lasts for a very long time ... for
women who got both modalities of treatment versus women who just
got tamoxifen," said Dr. Kathy Albain of Loyola University Health
System in Maywood, Illinois.
She presented findings from both studies at the American
Association for Cancer Research San Antonio Breast Cancer
Symposium.
"It is considered a landmark study in the clinical trials
literature because it is the only one really demonstrating the
survival advantage of chemotherapy added to tamoxifen," Albain said
in a telephone interview.
"Up until this trial, studies adding common chemotherapy drugs to
tamoxifen or tamoxifen alone were essentially negative."
For the study, the team followed nearly 1,500 post-menopausal women
with oestrogen-receptor positive breast cancers that had spread to
at least one lymph node.
Some of the women got both tamoxifen and a chemotherapy drug known
as anthracycline, and some got tamoxifen alone.
The team found that the women who got the chemotherapy were 24%
less likely to have their cancer come back.
They were also 17% less likely to die during the 10-year study
period, but this finding was just shy of meeting statistical
significance.
The team also found that giving tamoxifen after chemotherapy ended
instead of during chemotherapy improved a woman's survival
chances.
In a second study led by Albain, published in the journal Lancet
Oncology, the team evaluated whether the Oncotype DX test can
predict which women would benefit from chemotherapy.
The test examines 21 genes from a tumour sample to see how active
they are, and produces a score that predicts chemotherapy
benefit.
It is most commonly used in women with oestrogen-fed tumours
whose cancer has not spread to a lymph node.
But Albain's study suggests it may also be useful in identifying
women whose tumours had spread that would not benefit from
chemotherapy.
Albain said a large clinical trial is getting started that will
confirm whether the test is effective, but that will be expensive
and take many years.
Meanwhile, she said, some doctors like herself plan to use the test
on certain patients to give them more choices about their breast
cancer treatment options.
