Tamoxifen
Still Promoted for Many Breast Cancer Cases
Tamoxifen helps prevent breast cancer in women at
high risk for the disease who have also had their ovaries removed as
part of a hysterectomy, says a study in the Journal
of the National Cancer Institute.
Commenting
on the new findings, Dr. Jay Brooks, chairman of hematology/oncology
at Ochsner Health System
in Baton Rouge
says this "reaffirms that tamoxifen is still a tremendous drug for
prevention of breast cancer in women who are at a high risk for development
of the disease.”
The initial findings of the Italian clinical trial
found tamoxifen offered no reduction in women's risk for breast cancer.
Other European trials, some of which looked at women with different
risk profiles, had not found a reduction either.
An earlier and much larger US study, the National
Surgical Adjuvant Breast and Bowel Project (NSABP) Breast
Cancer Prevention Trial, had shown that tamoxifen could cut the risk
of estrogen-receptor-positive breast cancer - tumors that grow in
the presence of estrogen.
In fact, that trial was halted early, because the
risk reduction in invasive breast cancer was so striking.
In the latest study, the authors presented 11-year
follow-up data on more than 5,400 women who had undergone a hysterectomy
(including having both ovaries removed) and who had been randomly assigned
to receive tamoxifen or a placebo (inactive substance) for five years.
Ovaries make estrogen, so removing them ensures
that no extra estrogen - which can fuel some breast cancer tumors -
is being produced.
For women at low risk for breast cancer, disease
rates were similar whether or not they took tamoxifen, the researchers
report.
The situation was different for higher-risk women.
In that case, women taking tamoxifen had lower rates of hormone-receptor-positive
breast cancer than those taking a placebo.
There was also a greater reduction in risk for tumors
that were both progesterone- and estrogen-receptor positive, than for
tumors which were estrogen-receptor positive and progesterone-receptor
negative.
Women in the tamoxifen group also had more side
effects, including hot flashes and heart problems. These are noted
side effects of the medication. A woman's cardiac risk needs to be
assessed before she is started on tamoxifen, the authors state.
The new study points to the pioneering work that
the NSABP did back in the 1990s, says
Dr. Brooks.
"Tamoxifen is still an excellent drug for prevention
of breast cancer and is underutilized," he adds.
Another expert says newer medications can help,
too.
"Tamoxifen does decrease the risk of invasive breast
cancer," says Dr. Alison Estabrook, chief of breast surgery at St.
Luke's-Roosevelt Hospital in New York City. "We're hoping that the
new aromatase inhibitors which are being tried now for prevention will
reduce the risk of breast cancer, which they should."
Aromatase inhibitors, which lower the amount of
estrogen in the body by blocking a key enzyme, have far fewer side
effects than tamoxifen.
Another medication, raloxifene, also has fewer side
effects but does not prevent noninvasive breast cancer, whereas tamoxifen
works on both, notes Dr. Brooks.
Always consult your physician for more information.
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