FRIDAY, Oct. 21 (HealthDay News) -- The breast cancer drug
letrozole, marketed as Femara, may be more effective than tamoxifen
at preventing the return of breast cancer and improving survival
among older women with hormone-sensitive breast cancers, a new
In the study, published online Oct. 21 in
The Lancet Oncology, the researchers updated data from an ongoing study of about 8,000 women, which compares the two drugs alone as well as the use of both Femara and tamoxifen sequentially.
Femara outperformed tamoxifen in terms of breast cancer
recurrence and survival, the study found. Moreover, giving Femara
alone to women was more effective than giving it sequentially
following tamoxifen. The new study was partially funded by
Novartis, the drug company that makes Femara.
The hormone estrogen feeds hormone-sensitive cancers, and
blocking it may help stave off a recurrence. Femara is part of a
class of breast cancer drugs known as aromatase inhibitors. These
drugs block the body's production of estrogen via the enzyme
aromatase. Tamoxifen is a selective estrogen receptor modulator,
which means that it acts like estrogen in certain tissues, but not
in others, namely the breast. Aromatase inhibitors are given alone
or in combination with tamoxifen.
After an average eight years of follow-up, the team of
researchers from the United States, Europe and Australia found that
women who took Femara for five years after breast cancer treatment
had a "20 percent reduced risk of their breast cancer coming back
and were 21 percent less likely to die, compared with women given
tamoxifen alone," one of the lead authors of the study, Meredith
Regan of the Dana-Farber Cancer Institute in Boston, explained in a
journal news release.
Neither sequential treatment of tamoxifen followed by Femara, or
in the reverse order, significantly decreased the likelihood of
relapse or death compared to Femara alone, the team reported.
"Femara alone is the best way to go," said Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City. "The hope was that the combination would improve survival, but this was not the case," said Bernik, who was not involved with the study.
Breast cancer survivors who are being treated with tamoxifen
should discuss their options with their doctor. "Talk to your
doctor about switching to an aromatase inhibitor," Bernik said.
"Tamoxifen is still an excellent drug, but the aromatase inhibitors
are better. If the plan was to switch drugs, you may want to talk
to [your] doctor about going straight to the aromatase inhibitor,"
Dr. Hannah Linden, a medical oncologist at the Seattle Cancer
Care Alliance, said that many women don't want to take these drugs
because of a fear of side effects or the desire to put breast
cancer behind them. "The study stresses the importance of taking
these medications," she said. This is not to say they don't have
their share of side effects; they do, she noted.
Serious side effects seen with Femara include bone fractures and
increases in cholesterol levels. Some research has suggested that
aromatase inhibitors may also increase the risk for heart disease.
Tamoxifen side effects may include blood clots, strokes, uterine
cancer and cataracts.
Dr. Maura N. Dickler, a breast cancer medical oncologist at the
Memorial Sloan-Kettering Cancer Center in New York City, said that
aromatase inhibitors have been her go-to drugs for women with
estrogen-positive breast cancers for a while.
Some women report joint pain and other nuisance side effects
from aromatase inhibitors and have to go back to tamoxifen, Dickler
said. "In these cases, getting in an aromatase inhibitor for some
time is beneficial," she noted. "We can individualize treatment
based on the side effects and the tolerability for each woman."
Cost may be an issue for some women, but the gap in price
between the two drugs is narrowing, Dickler added. Femara is now
available as a generic, which helps reduce its costs, but tamoxifen
is still probably less expensive, she said.
Overall, "this is an exciting update with longer follow-up,"
Dickler said of the study. Since last results were reported in
2005, there was a 32 percent increase in the number of women who
had a relapse. "These women can do well for a long time and still
relapse many years later," she said. "It just reminds us that women
relapse during year five through 10 as much as zero through five.
Breast cancer is an indolent disease and you can remain disease
free for a long time, but relapse can still happen."
To learn about breast cancer treatment, visit the
U.S. National Cancer Institute.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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