Here's what AP said:
By Paul Recer
The Associated Press
W A S H I N G T O N, April 6 - A drug
found to prevent breast cancer in half
of high-risk women also causes
serious side effects, researchers
cautioned today, leaving women with
a complex decision about the best
course to protect their health.
"The results tell us
that breast cancer can
be prevented, but
there is no simple
take-home message,"
Dr. Richard Klausner,
head of the National
Cancer Institute, said
at a news conference
today. "There are
important and serious
side effects from this
drug."
Because the issue
is so complex,
Klausner said the
cancer institute is
developing guidelines
to help women and
their doctors decide
when to use the drug,
tamoxifen.
Tamoxifen should be used only by
women at high risk, Klausner said. It
doubles the risk of getting endometrial
cancer, although that risk is about equal to
that of women on estrogen replacement
therapy. Tamoxifen also causes a tripling of
risk for a blood clot in the lungs, a potentially
fatal disorder.
Evidence of Prevention
Nevertheless, tests of the drug, first reported
over the weekend, mark "the first time in
history that we have evidence that breast
cancer can not only be treated, but also
prevented," said Dr. Bernard Fisher, an
Allegheny University professor and scientific
director of the study that involved more than
13,000 women.
Tamoxifen has been used for 25 years to
treat breast cancer, but the study is the first
to show the drug can prevent the disease in
some women. The drug is known as an
"anti-estrogen" because it blocks the effects
of the hormone in some tissues and retards
growth of cancer cells that depend upon
estrogen.
Federal officials said the breast cancer
benefits from the drug are so clear that they
cut short a long-term clinical trial and notified
the 13,388 women participants of the
findings. The 6,707 women in the study who
had been taking a placebo, or dummy drug,
will be told they could now start taking
tamoxifen, officials said.
Lowers Risk of Bone Breaks
As a side benefit, the study also showed that
tamoxifen lowered the risk in older women
of fractures of the back, neck or wrist due to
brittle bones, or osteoporosis.
Klausner emphasized that the proven
benefit of the drug is only for women at an
above-average risk of developing breast
cancer.
The level of risk depends upon a
woman's age, her medical history and those
of her mother and sisters, and her
reproductive history.
Breast cancer risk increases with age,
officials said, and they estimated that only
about .3 percent of women 39 and younger
would be candidates for tamoxifen.
The percentage of women at increased
risk goes up to 2.7 percent for ages 40 to
44; to 7.l percent for ages 45-49; to 9.3
percent for ages 50-54; and to 12.5 percent
for women aged 55 to 59.
Final Results Years Away
Klausner said it also is unclear just how long
women should take the drug. The study
lasted only six years, and some women took
the drug for less, he said. Final effects of
tamoxifen may still be years away, he said.
Despite the complexities and the
problems, Klausner said the major
unprecedented effect of the study is to prove
that a drug can be developed to actually
prevent a high risk group from developing
cancer.
"This is the first imperfect, but very
encouraging step," he said, toward drugs that
could protect people from lung, rectal,
bowel or prostate cancer. About 85 other
drugs are being tested for this preventative
effect.
In the study, the group of women taking
the drug experienced 45 percent fewer cases
of invasive breast cancer compared to those
taking placebo. There were 85 invasive
breast cancers among the tamoxifen group,
vs. 154 in the placebo group.
Women on tamoxifen also had fewer
non-invasive breast cancers: 31 cases vs. 59
cases.
There were 47 bone fractures among
those on the drug, compared with 71 among
those on placebo.
Serious Side Effects
But the side effects of the drug were
significant and serious. Among the group on
the drug, there were 33 cases of cancer of
the uterine lining, vs. 14 cases in the placebo
group. The drug group had 17 cases of
blood clots in the lung, including two deaths.
This compares with six cases and no deaths
among the placebo group.
In the drug group, there were 30 cases of
blood clots in major veins, compared with
19 cases in the placebo group.
In some women, tamoxifen also causes
hot flashes and vaginal discharge, officials
said. |
