Drugs Cut Bone Loss of Hormone Therapy
Bisphosphonates Counter Side Effect of Treatment for Breast Cancer
Dec. 14, 2007 (San Antonio) -- The bone-building drugs known as bisphosphonates can offset a side effect
of hormone therapy for breast cancer -- significant
bone loss that can lead to fractures, three new studies suggest.
Researchers from the Austrian Breast and Colorectal Cancer Study Group
report that the drug Zometa helped to build bone in premenopausal women taking
Arimidex for breast cancer. Arimidex is a hormone therapy used in breast cancer
patients that helps lower estrogen levels.
U.S. researchers found that postmenopausal women taking another hormone
therapy used in breast cancer patients -- Femara -- were less likely to suffer
bone loss if they received concomitant treatment with Zometa.
And British researchers say the biphosphonate Actonel helped to preserve bone
in women taking Arimidex.
(Are you concerned about bone
loss during your breast cancer treatment? Talk about it on WebMD's Breast
Cancer: Friend to Friend board.)
Hormone Therapy Causes Bone Loss
About 70% of women with breast cancer have tumors that are fueled by
estrogen, making hormone therapy a cornerstone of regimens to prevent
recurrences and improve survival.
Doctors have used the hormone drug tamoxifen, which deprives breast cancer
cells of the estrogen they need to grow, to slow tumor growth in these women
More recently, they started using the more potent hormone treatments called
aromatase inhibitors to shrink tumors. The drugs block an enzyme the body uses
to make estrogen, thereby slashing the body's production of estrogen
These drugs can be lifesaving, but suppressed estrogen levels increase bone
turnover and accelerate bone loss, says Adam Brufsky, MD, of the University of
Pittsburgh. He led the American study.
Bisphosphonates increase bone formation and decreasing bone turnover, he
"Aromatase inhibitors cause bone loss and these drugs can ameliorate
that loss," says Eric Winer, MD, a breast cancer specialist at the
Dana-Farber Cancer Institute in Boston who wasn't involved with the work.
Zometa is approved for preventing fractures in patients with advanced bone
cancer. Actonel is commonly used to prevent or treat osteoporosis in
The research was presented here at the annual San Antonio Breast Cancer
Zometa Helps Build Bone
The Australian study involved over 400 premenopausal women with early-stage
breast cancer; they received hormone therapy to prevent recurrence of breast
cancer. The women were being treated by tamoxifen and Zoladex, or Arimidex and
In addition, half the women received treatment with the bone-building drug
Zometa. The medication was given once every six months for three years.
Bone density measurements of the spine were taken at the beginning of the
study and two years after treatment ended.
Results show that women who did not receive Zometa during hormonal therapy
lost 6.3% of their bone mineral density.
In contrast, bone mineral density increased by 4.4% in women who took
Zometa, says researcher Michael Gnant, MD, of the University of Vienna in